496HO Beep-Beep alarm....then
 

Out of the blue during Saturday's OM Poker Run after purring like a kitten a couple of weeks before, I start my motors and start getting this annoying double-beep alarm every 30-45 seconds all day long for what sounds like both motors (double-beep, then 3 seconds later double-beep again).

In addition, while running 4k+ on the RPM (again hearing this double beep all along) I would suddenly get a solid loud alarm that would not go away until I came completely off plane, at which time I could immediately pop right back up and run for a few minutes before the same thing would happen. If I stayed 3500 or less no solid alarm???

One motor actually stalled twice in gear at idle while approaching a card stop.

The the day after the run while leaving the marina, upon first starting the engines, they both sort of sputtered and died. But re-started fine again with the double beep alarm for each and hitting the solid alarm if I really got on it.

The only common denominator for both engines since running perfect the last time i ran it, was installing a t-fitting in the raw water feed hose approximately 4 inches behind the pump for a fresh water flush system which yes is air tight. Did all the obvious and cursory stuff like check connections, drive oil level, engine oil level etc. etc. and all were perfect.

Engines did not go in to guardian ( I tried to make them) but one motor later in the day during the run did seem to only want to reach 3700?

First off, what the heck is the double beep alarm for?

Secondly as i read it there are advertised only three alarms:
1) Engine oil pressure (one reads 40, the other 30 psi)
2) Engine temperature (gauges at 160, all four risers cool to the touch)
3) Drive reservoir level (both reservoirs are at the max line?

Any thoughts/experiences???

There are at least 26 different faults that can cause a "soft"alarm (two beeps per minute). Unless it's a coincedence, and it could be, it has someting to do with the flush fitting. Along that line, the two faults most likely to be set would be Seawater Pressure Low or Exhaust Manifold Coolant temp High.

If the risers are cool to the touch, it may not be the EMCT, but still could be low Seawater Pump pressure. Thats just a guess of course, and a scan tool or Smartcraft display are the only way to find out for sure.

By the way, you were in Guardian Mode as soon as you got the soft alarm, and when you go over 3500RPM, it will turn to a "hard" alarm (constant warning horn).

Dave

That's some pretty logical thinking. I know I'm not the only guy who has installed a fresh water flush t-fitting in the raw water feed hose, and I know the hoses themselves are closed off with airtight shutoffs as well as the screw in cap for the perko fitting, so why me and no one else if assuming it was water pressure related?

Where is this sensor? Is it the one with the wire lead connected to the raw water pump itself witht he pitot tube running to the pressure gauges? I got good readings on the pressure gauges too all day?

If I disconnected would it go away?

There's actually another local single 496HO (we just spoke on the phone) who i found out has been having the same exact symptoms/problem since installing his Perko version of the flush kit, only his motor will actually stall completely out once he's on it hard at 4000 rpm. Consistent double-beeps then full alarm etc. Scan tool said nothing, MAP and ECM both chaged out with no results etc. Somehow the hose must be causing osme sort of vortex or flow distortion to fake out the sensor (wherever it's located) sending false signals to the ECM of lessened water pressure.

What I don't understand is how others on here with basically the same basic flush kit setup has not experienced similar problems assuming it's water related pending gettnig a scantool hooked up.

Thinking out loud again...if the coolant/anti-freeze was low, would it give a similar alarm sequnce? If so, how low does anyone think it would have to be before it kicked in? Mine is a tad low from two winters of weeping a little bit, but doesn't really appear to be what I call excessively low.

Well good, bad, or indifferent, I just ordered the Merc scantool from Rinda to be received by Friday. I'm tired of having these little grimlins and not get immediate satisfaction as to what my problem is so I can gitter-dun. Had them throw in the adapter for the 502's as well.

Rick - keep us posted on if the flush kit is the culprit.

Da Svidanya

if it is a plastic flush adapter with the lil spring in,,, throw it out . their junk. they causer airation in the water. the original design of these type of units is 15- 20 years old and does not with stand the pressures put to it by todays standard factory engines which by far out perform engines from 15 - 20 years ago.

The Rinda scan tool doesn't always point directly to the cause of the soft double beep. I had a SeaRay with a bad IAC that I found by checking readings from the other engine and doing a time consuming comparison. Would have been simpler if I had TWO scan tools!
Good luck with this one.

Just think. Once you own your own scan tool, you're one step closer to being a surveyor!

Nowadays, A scan tool is money well spent.

yeah well guess what mercury marine just changed everything. all the new products like smartcraft can no longer be setup without a laptop. you used to be able to setup everything using the system view but not anymore. everything is going to have to be setup by the laptop. my boss just bought the setup last year and it was close to $9,000 for everything. you also have to update the computer every 3 weeks because they are adding more and more stuff to their line up. they say the reason for doing this is to cut out the mom and pop marina's and the do it yourselfer's. the verado engines pcm can see up to 250 fault codes. i am mecruiser efi3 certified,dts, and i just went to introduction to cds and that is where i got all this info. as for you 496 i have seen alot of those cheap exhaust sensors go bad especially being if they are being used in saltwater. they also just changed the exhaust manifolds to cast iron. duh that was a no brainer. saltwater and exhaust manifolds not mix. oh and if you are running in saltwater and that sensor is bad good luck getting them out cause they are made of cheap plastic and get packed with saltwater and snap clean off. i also have seen the a lot of those water pressure sensors go bad they are located down by the pump. good luck. oh and as for the rinda tool they work ok but it still is not as good as the ddt or the laptop. mercury marine also is no longer going to offer cartridges for the ddt.

I'm happy there will always be carbs. to work on...:D

Just a thought for comparison, but my Perko pieces are further away from the pump. They're behind the motor actually, maybe 1.5ft from where hose comes through transom. Maybe if they were moved further away the water would calm down some?

Could it be your sea pressure sender just because you were messing with the pump? I had my sea water pressure sensor go bad because I forgot to unplug it when taking the pump out to change the impeller. It sort of fell/dropped down when I took the pump loose and the wires pulled on the sensor. I was getting hi sea pump ckt at idle and it was showing around 46psi on the Diacom software. I could take a pair of channel locks and squeeze the sensor and cause my readings to return to normal. $90 part:mad:

I'm pretty sure i didn't do any damage to the sensors as it was no different than changing out the impeller for me.

Definitely no spring loaded Perko kit with the spring to rust out. Just plain-Jane t-fitting.

Moved the separator & boost pump off of to the side, disconnected the pressure sensor, dropped the pump, used a small PVC saw to cut the hose clean, disconnected the forward short hose piece, inserted t-fitting, inserted other end into hose all lubed up with soap/water, lifted & reconnected pump to bracket, re-connected pressure sensor, re-installed/connected separator & boost pump, installed serpentine. Same on the other side. Then did a once over QA check to avoid a self inflicted wound by burning an impeller etc.

I then fired it up on the lift one motor at a time for about 10 minutes each to do a leak check at all points etc. and even ran it at 1500 rpm for about 30-45 seconds, no alarms, no leaks (see picture of transom shot with water exiting drive w/ silencers on). One week later i put it in the water and voila! BEEP-BEEP!

I'm replacing a weak motor on my lift today then I will hang it, and do a thorough once over while on the lift where it's easiest just to be sure the sensor connectors are secure in place etc.

As you can see I simply used a 1.25" rigid PVC t-fitting, brass adapters, 5/8" rigid non-collapsible PVC hose, and my own idea of two way Y splitter shutoff w/ single Perko fitting. The Y splitter BTW is airtight when closed, plus the cap is on tight on the Perko. No leaks after sitting/running all weekend.

The Rinda tool is as far as i need to go on a set of 496's. If it doesn't tell me exactly what, it can certainly tell me what is NOT and close in on the culprit. I'm hoping I'll get in there disconnect the connectors on the snesors, re-connect firmly, and the bug goes away. I might even rotate the t-fitting a little more downward just to try and create a different dynamic inside the hose.

The other 496 I mentioned above with same only worse symptoms is getting Mercruiser involved (new boat under warranty dealer installed flush kit) and we'll be sharing notes. Plus the other thing is the two stall incidents i had, and the crappy startup the next morning?

I am not sure what effect this would have but I notice your fitting is a 90 deg angle. The fitting I received with my kit is more of a 45* and the angle is away from the flow. See pic.

Makes sense to me, but it would seem to me to only have affect when flushing? When I op-checked it by flushing the weekend before there was no alrms and everyhting worked great. I simply did what a few others on the board had done, and gone to the local THD store for the parts. Others works, mine "maybe" is not. Won't be any confirmation until the culprit is found.

BTW where did you get the angled t-fitting? Which kit? Can I get just the fitting by itself?

The Angled fitting came with the Mercury 496 flush kit. The instructions are very specific in the direction and distance to mount the fitting. If memory serves me the hose was cut 7" away from the pump which actually puts it behind the motor mount.

Rick - what's the deal with all that rust down there???:D

I ordered 2 new Merc units which should have arrived at my house by now so they go in soon. You can check out the difference if you want. My take on it is that you cannot use the PVC cause you won't get a good seal (it will suck in air) without the barbs and a super tight hose fitment. The distance away from the pump could also be a factor along with the angle of the T that could cause a disruption in laminar flow this introducing more cavitation to the impeller and causing a low water pressue of even "overheating" issue. I would ditch the connector you used and get the Merc angled part and you should be fine... unless you want to use that as the excuse your boat isn't faster than mine :) :) :)

Yeah, this past winter put a hurtin' on the hardware. Got most of it cleaned up while it was apart and painted. Problem always is the bilge holds so much stagnant moisture.

The PVC does have barbs. Made it a biotch to get the suckers int the hose which is rigid as hell. Plus the clamps on there as tight as I can get them. Again i have plenty of gauge pressure and there are no temp alarms which are either there, or they're not. Risers cool to the touch immediately off plane, plenty of water out the back. The mystery is the 2 beep per minute alarm that popped up suddenly, immediately after starting & every 60 seconds consistently. High demand/high RPM a solid alarm but no guardian shutdown except one motor refuses past 3700 (turned out to be fouled injectors again like the other motor a few weeks back).

7 inches definitely behind the motor mounts and almost impossible to get on. Mine are in the 4-5 inch range. I would almost have to go back 24 inches from the pump to clear the mount and manifold purge valve. The 496 has two hose sections, one from the transom to the purge valve, and one from the valve to the pump itself which is where my T is. If there's no flushing, then I don't understand how the angled fitting would matter other than assissting in flush directional flow, especially with weak water pressure. It appears to me Merc did that only to ensure good directional flow when flushing. My post-op check flushing the week prior worked great and instantly no alarms.

If you still have those directioons do me a favor and scan them and post them if able.

Hey Vype, how's Moscow?....

I wonder if because the Tee is so close to the pump that the pump is actually sucking air from the Tee. I imagine that the strength of the pump is enough to do that. If it is sucking some air, it may be aerating the flow enough to cause the alarm and not actually have water flow problem. I'd move the fitting back as far as possible and try it again.

The flush lines with the Perko cap on tight, and the Y valves closed is air tight. But there may be just enough from the void in the line via vacume to cause some aeration "in theory". I'm going to try swiveling the T more downward to see if that has any effect. Again this is all assuming its the flush system and not someting else.

Rick, do a scan when you get the tool and copy and paste the results here. Dave N is good at reading them and locating the hiccup.

Your molex connector on each motor is capped and located right around the oil filter area. Might be hidden but it should be there. Make sure you watch the cord so it does not get into the motor belt.

also remember that when you are running on the hose, you are forcing water into the system at hose PSI so that is different than just sitting in the water using the pump to suck through the drive.

i would agree with t island it looks like a sch 80 pvc t is to thick and to close to pump causeing too much turbulance in water flow resulting in air bubbles on sensors. plumbers advice.

Rick - Moscow is AWESEOME! I liken it to the old Wild West in that there's a lot of money (mobsters) as shown by all the Ferrari's, Lambo's, Bentley's, etc. driving around and the high end shopping available. It's also a place that you can get ANYTHING you want at just about any price. There are few real laws enforced and it's a fun but wild place to hang out. The scenery is impressive on several levels; the buildings and monuments are nice but the girls are freakin' GORGEOUS and they're everywhere! Lot's of fun overall and great weather (mid 80's and sunny the whole trip).

Thanks guys for advice. I finally got my lift motor changed and the boat on the lift yesterday. I plan on diving into the mystery a little later on. I'll definitely be taking what's said while deep in it. Scan tool may not arrive until tomorrow. I'll be taking off to Ocean City, MD where we have a timeshare at ocean Pines for a week. So I may not get it totally resolved until i get back unless i get lucky and find some self-inflicted wound/s today.

Dave Moscow sounds awesome. I've always heard that about the place. Can't wait to hear your debrief when you get back.

I fought this problem off and on most of last season..It started about 2 weeks after the impeller went to pieces.. However I found all the fragments.It wud double beep every 60 seconds. But the next time I went out it was fine.I had local marina put a scan tool on it, but it was not acting up then and I was told it does not read soft alarms unless its actually alarming at that time.

Well I got one motor to stop the double-beeping and run fine by rotating the T more in a downward direction. The other has reduced to intermittent. I lowered the T angle as much as I could yesterday and will test today to see if it helps. I also went around and cleaned all the connectors i could find especially the water pressure sensor on the pump itself. I put my new scantool on it and got the usual Pitot/Steer CKT faults, but I also got Fuel LVL Hi & Fuel LVL1 H pop up too. But I don't have a list to determine what they may mean if anything.

Well I fouind out thru searching the forum that the Fuel LVL/LVL2 codes are like the Pitot/Steer codes, they will always be there looking for options that the Smartcraft DTS can use and therefore are to be ignored. Except checking seconds to verify fault code memory erasures (Thanks Dave N).

Well now I'm off to verify if the double-beeping on the port will go away.


hp500efi what are you referring to when you say "molex" connector? I'll look to see if I see any capped connectors in that area.

Got a IAC Output fault today on the scantool. Actually got it once before, erased and it didn't pop back up. Took it off after my test run today, and it was "charred" around the bottom of the connector? Sooo, I'm gonna replace that and hopefully the soft alarm will go away like it did on the other motor.

Reflecting back it seems I did for a brief moment messing around under the hatch smell a faint odor of burnt plastic or something, and even made a quick look around both motors, and found nothing (burnt portion of plug is out of view unless off the motor). The scan tool of course started consistently giving me the "IAC Output" fault; "PCM Error" if I attempted the IAC test; and only "90% power" available.

I don't honestly think the fresh water flush kit I installed had anything to do with the 2 per minute beeps, and that it was purely coincidental. If it had, then I would suspect the "Sea Pump PSI Lo/Hi" fault would've popped up now that I know there is one and have my own scantool. Of course I won't know for sure until I replace the IAC valve this week and re-test. I will get an additional one just in case the other motor's IAC is not far behind (since in the beginning I was getting a double set of 2 per minute beeps).

Now that Dave N provided me the Fault code list, a lot of things makes sense now in terms of the alarms etc. This has been a PITA but also a great learning curve for diagnosing future symptoms/issues myself.

Seems pretty clear that the IAC is bad on one engine. On the other engine that is no longer giving an alarm, what faults were stored in the freezframe memory?

The usuals plus overspeed, guardian, and yes the IAC. But I had gone thru a remove, clean, replace cycle in the beginning in addition to re-positioning the T-fittings, and the IAC code never appeared again in the active fault listing engine off switch on, and while at idel. I'm buying a second one just in case the other decides to take a dump as well. I also removed that harness connector going to the transom with no results either prior to the IAC discovery.

I ran the individual IAC test where it asks you to increase/decrease Idle RPM at normal operating temp on each engine. The port said PCM couldn't Error. The starboard showed the % increase but the engine did not increase in actual RPM (that I noticed) thru 50%. I pulled and looked around the starboard (now good side) IAC and saw no signs of burnt or charred plastic like found on the port IAC.

While on the subject of running individual tests, to do an injector test it says to unplug/disable the fuel pump. Does that mean only the boost, or both pumps port & starboard?

I have found and cleaned a lot of crud in both injector sets this year, and I'd like to run the injector test but I'm not sure of the fuel pump warning.

Also any gouge on running the Auto-test?

Didn't somebody back in post #9 mention something about the IAC? You guys have no respect for us old white hair MFers!

In Reckless' case; it has nothing to do with lack of respect - more like the hardness of his head. LOL :drink: :drink:

In the help section of my Diacom software this is what it says about the injector test;
"The Fuel Injector output test allows individual fuel injectors to be actuated in order to verify their operation. The fuel injector under test will be fired at a rate equivalent to 1600 RPM. This test will help the technicians verify that a particular fuel injector is receiving a command signal from the PCM. This test will not reveal if an injector is clogged, internally leaking or mechanically worn."

As far as the IAC test, I have never been able to get it to work on any engine. The symptoms of a failed IAC are usually pretty appearant and will set a fault most of the time, so it's not really critical, but it would be nice if the test actually worked.

It's really strange how both engines had an IAC fault right after the flush kit installation, and niether engine showed any symptoms. Just proves the importance of a having a scan tool.

Dave

It's called good old fashioned perseverence Bill...:et:

Ed it wasn't ignored, just couldn't be proven at the time until after i got the scantool in hand and THEN was able to isolate it. Otherwise I would've been pulling and yanking for nothing.

Dave it's good to have verified the IAC test doesn't work. The bad motor definitely shows "PCM can't initiate the test **Error** or something to that effect and 90% power. There was never any "Water pressure" faults at all like one would assume if it was the pump sensor being fooled. I picked up my two new IAC's today and will install shortly and verify the fix, or a continued Grimlin.

Yeah my book says the same for the Injector test, as does the scantool warning when entering the test. What the book doesn't say specifically for 496's is do we disconnect both pumps (boost & primary), or is just the boost sufficient? I'm afraid to try until I find out for sure though i don't think there's any indication of problems with the injectors since I cleaned both motor sets..

To minimize flooding when doing the test, I would disconnect both pumps and even bleed off the pressure at the schrader valve before doing the test.