Reckless32

Had some issues lately with my pair of 2004 496HO's that is really bugging me out.

Last weekend replaced a dead battery out of two. On Sunday both were dead after running all day before. Jump boxed it and pressed. Hit thetrim switch and suddenly both motors died with both batteries dead....Fast forward a tad.

Now I have two new batteries. With one batt switch set to #1, and the other to #2. Starboard volt meter reads 11-11.5 volts in spite of throttle setting so it appears bad as one in my mind, separate issue.

Volt meter for port engine reads strong and rises when revved.....Let's fast forward again.

Sunday pull away from dock thinking ZI could get thru and at about 2-300 yards port engine starts sputtering and dies. Start it but it won't keep ruinning even if I pump throttle in neutral. Limp back to base. Pull fuel separators and they appear to have some red rusty crud. Fire back up, everyhting seems well and pull away again. Virtually same thing happens. Went to trailer it, and now both engines are doing the same thing. Will start with some difficulty, but hten sputter and die. Pump the throttle in neutral and I will get some sputtering and a little back fire before dying. Now WTF...?!

Pulled one of the two in-line filters (my automotive version replcement attempt wouldn't fit threaded adapters) so I unscientifically simply blew thru it to see if maybe it was clogged. The air passes thru it without restriction. Of course i don't know if that has a hill of beans to do with liquid fuel's ability to pass thru it?

So here I am with BOTH engines not wanting to run (start but not susatained run) and also what apears to be bad alternaotr on one engine which shouldn't prevent both from running even when battery switch is set to both at least in my mind.

So my quagmire is am I looking at a fuel restriction issue (haven't replaced a seemingly unstricted set of in-line filters yet, or an electrical issue of some freakish sort involvng that one bad alternator or some other problem caused by an alternator going out?

If an inline is clogged can you still get air to pass easily?

Thoughts or ideas?

Ted G

iTrader: (1)

The elec systems on EFI engines must be kept seperate-no running on "both". It messes with the ECU and makes it run poorly.

Rippem

check the screen on the inlet side of the high pressure pump for varnish.

Reckless32

Insptech I'll admit I have done that and it could possibly be involved with my issue/s right now. I found out recently from the factory to keep each switch set on separate batteries at all times except for Both in a pinch only to start, but had no previous issues when I left it on both over the last couple of years til now.

For discussion sake anyone, if it did mess with the ECU/s can I reset them by disconnecting the battery's for awhile to reset?

Back to the other possible issue, fuel. IF the inline's are clogged could you detect it by simply blowing thru the filter and sensing restriction or no? I'd rather avoid the expense of $100 for two if it's not needed. Also is it difficult to get to the inlet screen? Do you have to remove the separator etc. to do so? My right leg is in a knee brace (popped a knee-cap tendon on July 4th) so my ability to bend/squat etc. is limited right now....

txriverrat2001

Can you detect a clogged fuel filter by blowing air through it? Yes. If you can pass air through the filter without any restriction - you're good to go.

Back to basics - In order to determine whether you have an ECM or fuel problem you'll need a scan tool and a fuel pressure gauge. The two will guide you to the root cause of your problem.

Something to think about - One engine was giving you problems - you identified a foreign substance in the filter - then the other started to give you problems. Most twin engine set ups will have two fuel pickups at different heights in the tank. This prevents both engines from dying simultaneously when your extremely low on fuel. Mine has the genset the highest, then the port motor (without P/S), then the starboard.

If you problems started with the one motor and something odd in the filter - then I would take a fuel sample in a glass jar and see what you've got.

Invest in a Fuel pressure gauge and take a reading - I think 34-38lbs would be appropriate - somoeone else may have the exact figure as I'm not near my manuals at this time.

Rinda Technologies sells a simple scanner for around $450. It's pretty self explanatory and with a little reading you'll understand what the codes are and how to interpret them.

Also - when you place the throttle at 50% or higher, the ECM will detect a flooding situation and shut off the fuel delivery to the cylinders. It does no good to "pump" the throttles on a Fuel Injected motor whatsoever.



Good Luck!

Capt Ross

Reckless32

Thanks Ross for the insight. A friend mech came over yesterday and put the scanner on it. I also showed him what remained of my fuel sample (evaporation setting in) and it defintely has a rusty sort of crud in it. The scanner revealed nothing other than yes, the one motor has a non-functioning alternator, but I knew that already. He didn't have it with him yesterday, but today he will bring over the fuel pressure gauge to hopefully verify in fact it's a fuel issue with the most likely culprit being the inlet screen on the boost pump. If the separator had that much gunk in it, then the screen must as well assuming it came from the tank, and not a deteriorating separator canister itself. I say that because the inside (meaning inside of the O-ring seal area) of the canister was rusty, appearing like the rust possibly came from the canister and not the tank??? I have since pulled the new separators to check the fuel and it appears clear to the eye so far. I'm going to re-check today just for kicks. The rusty crud canisters were installed fall of 2005 BTW. The other curiosity is how does fuel rust anything (assuming it did inside the cans) without the presence of waterin the fuel????

Anyway, I know approximately where the boost pump is located, so what are the basic steps to get to the inlet screen/line to clean it? Is it easily accessible? Probably remove the separator canister first I'm sure, then what??? I'm gonna attempt it (curiosity is killin' me) with the gimp leg if I can bend over that far in a locked brace with tools....

baja36ft

Sounds Like You Have Water In The Fuel Rick.
Change The Filters Again And Try It.

Reckless32

Thanks Stan. Dave L. is coming back over at 4pm to check fuel pressure etc., plus like you said, I will not only check, but replace the separators again. We're thinkin' though the boost pump inlet screens (which come from the tank & in-line filters first before going to the separators) are possibly clogged with the crud I found in the first canisters. The substance was gritty like it was fiberglass dust or something in addition to being rusty colored?

Rippem

Reckless32

Rippem' I've got my fingers crossed, but won't count my chickens before they're hatched as my dad used to say....