Approximately 225 hours on engine. The weird thing is this didn't start to happen until after the engine was rebuilt with a new long block. Prior to that, never had this problem. I'm going to try the key cycling next and recheck the fuel pressure again and then after that, maybe I will take you up on your offer to try one of those pumps.

thanks.

Scan the motor for codes and look into the history ? Will add from before in my post - you are looking at the ranges for these sensors to be within parameters or out of range - IAC, MAT, Coolant Temp and MAP.

Also internal check valve problem in the fuel pump,

IMO possible fix is in this post.

That's a lot of parts changing - scan the motor for possible help - .

http://www.boatfix.com/merc/bullet/99/99_07.PDF.

OK. Will give that a try as well. Forgot to mention in my earlier post. I also replaced the coolant temp sensor over the winter as someone else suggested prior.

Not sure how the cool fuel works or is plumbed, but this sure smells of a vapor lock condition.

It is, 578 do you vent the hatch when stopped after running ? I asked earlier what engine is having issues, my old 502 mpi was always the starboard side, I think most common is port. ?

It could be possible vapor lock but as posted in post # 1, 2 and 3 almost does nt sound like it.

1 it was past mid Oct in New York - temps could nt even been warm at best, . plus he vents and leaves his engine hatch open after shut down. No report of this problem in the hotter summer months and said never happen before until I guess new long block installed. So what else changed ? Mechanical and or electrical or set up issue ?

2. in post 1 , he Reports advancing throttle helps but should nt have to. I agree you should nt have to. 8 out of 10 times if you have to advance your throttle on a MPI engine to start it or restart it, this can be traced back to an IAC or coolant temp sensor and or its connections and or its wire(s) having an issue

3. cycling the ignition key 3 or 4 times will get the engine started. Motors runs great all day no other problem reported. None of the other engines reporting this problem and he has TRIPS but did not see which engine is the problem one..

I still would scan this motor look for faults and look into the history.

the cool fuel set up is like a GEN II style but has a bigger fuel cooler and designed a bit different.

The fuel pump (electric) in the cool fuel uses the same bracket that needs the heat transfer compound on it to help the fuel pump pull heat away from it. It is wise to clean the bracket completely and reapply new heat transfer compound every so often. Possible check valve problem in the electric fuel pump that lets fuel bleed back or possible some fuel boil off, a slight form of vapor lock. I would not rule out a sensor or connection or wire to a sensor that I listed before. I do not think it was ever mentioned of scanning the engine. You can scan the other engines to compare the results.

After sitting for 2 hours you are saying the engine will start just by advancing the throttle CORRECT that's how I am taking it from post 1. ? If so that is not vapor lock or even a electric fuel pump issue.
.

Thanks BUP. Here's some comments on your comments...

It is the Port engine that is having the problem. It is a 2008 525EFI (at least all of the accessories are; the long block was replaced last August).

1) Problem surfaced immediately after the rebuild with the new long block which was last August but persisted into October when it was quite cool and re-occured this past Sunday when outside temps were in the 60's. Engine temps were quite cool, ie: water temp never exceeded 150*, oil temp stayed around 160*. I immediately raise engine hatches after shut down and leave them open for the 2 hours we are stopped.

2) Advancing the throttle will get the engine to start and once it's started, it runs perfectly normally. The problem is just with the start up.

3) I have not tried cycling the key 3 or 4 times yet. That is next on my list the next trip out. It is the port engine only having this problem.

I have not scanned the motor yet, but I will do that also the next time I'm down there. To reiterate, I have replaced the IAC, cam sensor, crank position sensor, coolant temp sensor, fuel regulator, serviced and flow tested the injectors.

Thanks as I thought advancing the throttle will start the engine per your post # 1. That is not vapor lock nor a fuel pump problem, This boils down to the ECM, connection(s) / connector(s), sensor(s) - Most likely a resistance problem somewhere in the circuit that are related to engine start up. Heat and heat soak can cause resistance problems also corrosion and bad grounds. Just saying.

New sensor(s) installed can still have problems because the sensor(s) all have a 5 V or a 12 volt circuit and a ground. The problem can still be within the circuit rather than the sensor itself. .

Like I said in one of my posts a scan might help about this problem. I would scan all the engines and compare.

Oh also I like your comment about "Here's some comments on your comments" I will use that statement as well for now on.

THanks again BUP... Here are my comments on the comments you made on my comments... LOL..

I have the Rinda / Diacom software on my laptop; will that give me what I might be looking for? I know I can get error codes from that, but what else should I be looking at?

Port side, pump is on the outside, probably the least amount of air circulation, next time you stop after running put an ice pack on the cool fuel :drink:

I think the pump is under the front of the engine with the fuel cooler. But, the thing to keep in mind is that this problem never occurred before the engine was rebuilt last August, so I think it is unlikely that its being caused by lack of air circulation. It has to be something that was caused in the process of R&R'ing the engine last August. That same engine was hauled out again over the winter for when I ripped out my Silent Choice exhaust. It's just not that easy to diagnose because the engine has to be run for a considerable amount of time, sit for an hour or two and then try to start it. Not really easy to just give to my mechanics and say figure it out..

What does R&R say about the issue, ya its wierd that it happered after the rebuild, did R&R rig the whole engine or just do the long block

Yes, they reassembled the whole engine, re-rigged and put back in the boat. They're great guys and have been trying to help, its just not easy to find because it only occurs when its been run for a while and sits for an hour or two and those times are generally not when the guys are around. I just spoke to the guys at Merc. Racing and they suggested that the next time it happens, take the fuel/water separator filter off and see if the filter is full. If not, then there is a problem occuring in front of the engine. If full, the problem is on the engine.

again never happen before and even with vapor lock that just comes out of the blue and never has before - then what changed - if anything.

Vapor lock that just happens and or fuel boiling off that never happened before - something causing it - mechanical, electrical, a failure - issue , and so on. Now if this was a new boat and started from day one then of course different story. You have to find the problem that is causing the problem but beforehand narrow it down to what changed. if any.

In his case motor starts just by advancing the throttle as he reported - this is not vapor lock. Advancing the throttle only and the motor starts RIGHT UP and runs great all day afterwards - again this is not vapor lock nor logically should not be a fuel pump problem.

It reminds me of a heat related resistance problem that applies to the starting circuit - sensor(s) connections and or wiring to them or even possible ECM or bad or loose ground(s).

Like I said with an MPI engine that starts by advancing the throttle 8 out of 10 times it has something to do with the IAC and or coolant temp sensor. I would look at your MAP reading as well especially after this heat soak takes place. Look at it before you start the engine and then reading while the engine is running.

problem IMO possible with any one of these, including the connections , and wiring circuits -

MAP
IAC
Coolant TEMP
MAT
Also would nt rule out TPS

Find someone that really understands the scan and the parameters

What about the heat transfer compound bup mentioned, may have been cleaned off and not reapplied during parts chachangeover.
Edit Oops.

This is why all the cool fuel stuff has been removed from my engines and replaced with Aeromotive pumps and bipass regulator's and -8 fittings 1/2 inch hose

Want to be very clear - boat sits hours later - you advance the throttle the engine STARTS RIGHT UP - LIKE NORMAL and runs fine and all day - is this CORRECT.

If so that is not a fuel problem nor a vapor lock problem, Can not believe if you told MERC all of this and the exact words they did not tell you to scan the engine.

Yes checking the fuel level in the fuel water sep filter is good way to see if you have a boost fuel pump problem that can not keep up pumping fuel that the engine needs and or keeping up with the high pressure fuel pump. it is a good laymans test out on the water after shut down.

To add is - Engine heat has to pretty darn hot to boil half the fuel out of the fuel water sep filter. No other engine is experiencing this hmmmm.

the heat transfer compound dries up over time and or flakes off over time. The reason its there is to pull heat away from the fuel pump. Funny how people all of sudden vapor lock shows up and never think about this nor the fuel that can boil out. Again if a problem just shows up that never happened before what changed ? in that case the heat transfer compound is not doing its job or hotter running engine temps or an electric fuel pump resistance higher than it should be .

Just saying this as an example not pin pointing to anyones problem. Unless your description is not what I keep asking you about to be 100 % clear. (advance throttle engine starts right up)

Call me and I will run your rig while you are at lunch. Problem solved:)

To be 100% clear... here's the exact scenario... Run the engine at 3500-4000 RPM cruise to lunch, approximately 30-45 minutes. Oil temp around 160, water temp around 150, 63 degrees outside temperature, water pressure at 25-30 psi (ie: very normal operating conditions). Have lunch, sit for an hour or two, engine hatches raised on shut down. Finish lunch, go to restart, turn key, engine cranks normally but will not start.

As I turn the key on the second go, I push the throttle forward to approximately 2000 RPM position and you can hear a cylinder or two fire as its cranking (you can hear the exhaust blast) but it will NOT start just by advancing throttle. I need to pull the throttle back to idle position and push forward again and keep rocking the throttle (ie: pumping the throttle back and forth) between idle position and 2000 RPM position while I'm turning the key and with each iteration of this, you can hear a few cylinders firing (like she's trying to start) and then eventually she fires up. The best way I can think to describe this is like a pull cord lawn mower. Pull the cord the first time, nothing happens.. pull the cord a few more times and you start to get a few coughs... keep pulling the cord and eventually, the engine starts..

Once it's lit, it stays running and runs completely normally. If I were to shut it down immediately and restart it, it will fire right back up. It's only on the first try after its been sitting.

It's the accelerator pump, ur a carb guy lol......... when you first turn the key to the on position can you hear the high pressure pump pitch change from high to a lower tone, this happens when its putting pressure to the fuel rail or does it stay at a higher pitch meaning there's no fuel to push

I had the same problem last year with one my 525s. It wasn't setting any codes so started swapping sensors between engines one at a time. It ended up being a coil pack. To this day I don't understand how giving it throttle would help a bad coil pack! Might be with a shot to swap them.

Were you having the exact same symptoms as I described above? How did you determine it was the coil pack??

I'd take your laptop out on the boat with you, hook it up while you are at lunch, and prior to cranking - key on, what does ECT say? I'm with BUP, my guess is this is engine control related - and the first place I would go if I was diagnosing.

Yep, that's the plan.

How many times does it take turning the ignition key over ' crank engine over to get it to start - it looks 3 times -

The scenario is - 1. we have no start turning key over - throttle at idle setting, 2. then we have advance throttle turn key over again no start -3. then we have pumping the throttle and turn key over again the engine will start this time - Correct Anything on your part to add to this ???

Take advancing and pumping the throttle out of the mix - leave it at idle setting, turn the key only to on position - NOT starting mode / cranking mode - do you hear your fuel coming on ? if so do this same procedure 4 to 5 more times - key on - fuel pump running - when fuel pump stops turn key off - do this 4 or 5 more times - this is cycling the fuel pump - after that does the motor start
( leave throttle in idle setting and do not move it ).

This might take 2 people one at the key switch and the other to listen for the fuel pump running ? Sorry trying to narrow this down - it is always good to give out as much detailed info as you can plus the depth of it - trying to find out these problems.

I have more to post about your throttle plate setting and the IAC value - I will post it very soon.

You have sequence correct

Roger I am crystal with the sequence. Just staying with it and tying to follow along

And you're doing a great job at that... thank you for your help...

Past posts I thought you just advance the throttle on the second attempt to start the engine and it would start. Pumping the throttle with an MPI engine - the injectors are at the end of the line - throttle pumping has nothing to do with them spraying fuel like a CARB would. The ECM does and of course proper voltage and so on for the injectors to spray fuel - the JIST of it. That's why I am really curious to see if you leave throttle at idle setting and do not touch IT or move it - but cycle the fuel pump 5 to 8 times and then crank over the engine to start - I want to know what happens - if this starts the engine then possible fuel related issue / fuel pump/ check valve in the fuel pump or fuel boil off issue -

if no start on those attempts - advance the throttle on the next try - if it starts it is not a fuel related problem nor a vapor lock problem or fuel boil off problem. It is a sensor / or connection or a ground problem of some sort.

Sounds like a plan.. thanks again.

I pretty much was. Started cold and hot fine but if it sat a while after running it would start hard like you are experiencing. I pretty much tried everything else so I swapped coil packs and the issue went to the other engine. I spoke with mercury racing and they agreed that it was strange but it's been fine since the new coil pack went on.

Hey, ..... HI Five, ........ even if we cant diagnose the problem, your typing skills have greatly improved, good luck brutha

the ignitions coils in the later apps 0M953??? engine serial # and up were moved to upper back side. this help somewhat better against heat and heat soak compared to the past mounted.

I have brought up what has changed in your app and thought about some the things to double check and might help whomever whenever.

Asking how did you mount your sensors - questions are posted ?



Did you remove the throttle body for any reason ?

have you touched the throttle stop screw or adjusted it ?

Did you install a new gasket for the IAC and torque it correctly

Did you install the crankshaft position sensor and examine the SPACER that goes with it for the install. Was the spacer in perfect shape or a NEW SPACER installed ? VERY IMPORTANT HERE again very important.

Did you install a MAP sensor - if so make sure you did not damage the seal. And this sensor should lie perfectly flat on the mounting surface when installed.

coolant temp install - If I remember CORRECTLY should not exceed 2.5 turns when installing but might be wrong here. Sensor installed to seat the o-ring and do not over tighten. Also merc has always listed PST pipe sealant for the threads.

I know this 4 sure the MAT sensor is 2. 5 turrns MAX for the install and uses the same PST thread sealant on the threads.



Important INFO that might help.

The throttle plate adjustment is important here.

you have to remove the throttle cable off the stud and remove Flame Arrestor

You have to manually open up the throttle plate about 1/2 way and let it snap shut by itself. AFTER that there is 5 measurements that need to be taken with a feeler gauge thru the throttle body and throttle plate horizontal sections of the throttle plate - 3 top and 2 bottom positions with a feeler gauge to see measurements.

find the smallest gap with your feeler gauge in these 5 points of measurements. You are looking for 0.009 of inch clearance. If you do not have this - you have to adjust the clearance of the throttle plate against the throttle body by using the throttle stop screw. After the correct clearance is adjusted at the smallest section /position - open the throttle plate manual again half way and let it snap shut by itself - retest your clearance again with the feeler gauge to make sure it is correct - again at the smallest position section throttle plate clearance of your measurement like the first time go around still needs to read 0.0009 in.

Next is reinstall the throttle cable and flame arrestor. Hook up your scan tool and the run the engine reaching full warmed up normal temp. Next is - at IDLE SPEED fully warmed up engine you have to adjust the idle speed screw on the throttle body to a IAC duty cycle of 20 %. This is very important.

I took a lot of thought into this if all else fails in your testing - I think I have covered a lot that could possible help. Like I said before What has changed on your engine ? I thought of outside of the box thinking what could have possible changed here.

Still want to know about cycling the fuel pump not touching the throttle and then advancing it.to see what happens.

thanks BUP. my next step is to cycle the fuel pump and see what happens to figure out where to go next.

I know I wanted to get all that info I posted out of the way just in case if your issue remains because one of these days when it stops with the bad weather around here - I will have to get back to work non stop. Plus it was in my head and I did not want to forgot anything.

Cycling the key 5 to 8 times or even 10 times will tell a lot and if still no start but advancing the throttle and the engine starts will tell a whole lot as well.

So whats up with the triplet beast here ??? See I even put 3 question marks for the triplets.

Nothing to report yet. Haven't been able to get back out again yet.. You can be sure that I will report my results...

I did find one thing the other night when I was doing some other stuff, but I really don't think it has any bearing on the situation. It looks like some of the adel clamps that hold the fuel line down were stepped on and they are pinching the fuel line a bit. It probably happened when they put my engine back in this winter. I'm going to put new clamps down, but I doubt it has any effect on whats happening since it was also happening last summer.