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Marine Power 454 won't restart

DriftnDrink

New member
I have had my new boat for about 3 weeks now (1995 Mainship 37) and love it.
The engines are Marine Power 454's with 140 psi on all cylinders and about 900 hours. Throttle body fuel injection and electric fuel pump.
These engines start and run great although prior owner had financial issues and had let the fuel get to near zero (I think - fuel guage does not work).
After putting in lots of fuel and cleaning out the fuel filters it has run very well.
My issue has occurred when we go for an evening cruise and anchor for an hour or two. The starboard engine starts immediately but the port will not start at all.
The first time it happened I went back to the marina the next day and it started right up and ran great.
It happened again the next night and I finally got it restarted before I had to dock.
Engine cranks, seems like it gets fuel to cough for a few seconds and then it just cranks but no start.
I would appreciate any guidance that might be available.
It certainly feels like a fuel issue and I wonder about the fuel pump.
Almost forgot, this boat has a single fuel tank for both engines.
Thanks.
 
Ok - new to you, twin screw-900 hrs, single fuel tank, can't restart port engine once warm and shutdown normally.

Could very well be the fuel delivery system.

I'd start by taking a timing light and hooking it up to the problem port engine when trying to restart warm. If the light is flashing, spark is present, so the focus should shift to the fuel system.

Most EFI's will turn on the fuel pump for a couple seconds when the key is turned to RUN. After that, normal OIL PRESSURE is required for the pump to continue to run. I'd turn the key to RUN and then off, after the pump stops, a few times and then see if it starts. maybe the pressure doesn't have enough time to build up when warm. If that does work (but pump runs) time to get a fuel pressure gauge hooked up.

If the pump doesn't run when the key is turned to RUN, Time to get the test light out and probe the fuel pump circuit to see where the issue is.
 
No fun and no fix so far!

Mechanic #1 - replace distibutor cap and rotor (which were needed). No restart. Clean Idle Air Control Valve which appeared to have fine particles. Restarted (but I think coincidentally) since it was not a permanent fix. Since they are easy to replace and I found one at local parts store I replaced it and still have the same restart problem. No one has checked for spark because it appears to get spark and tries to restart but then just cranks. Fuel is spraying from the injectors.

Mechanic #2 - took the boat out for a ride and then shut down. After about 5 minutes it restarted ok. Air temp much cooler (about 80's compared with 90's when most of the problems have occurred). Back to the dock and again restart with no problem. He wanted to check fuel pressure but he did not have a fitting with an o-ring. He did not check spark since it was restarting. This mechanic suggested vapor lock since he had the hatch open and the air temp was cooler.

I researched vapor lock and decided to put in Sta-Bil and add some non-ethanol fuel. Long drive to marina with non-ethanol fuel but a chance to get a sandwich and listen to music. Left engine hatch open. After about an hour a little hard to start but it did restart. Ran great for an hour + ride back to home port marina. Let it sit for about 20 minutes and same old problem. Could not restart that night. Next day I restarted just fine. I also have installed a remote air temp guage and engine room temp has not gotten above 97 degrees but still have the restart problem. Not appears not to be vapor lock.

Soooo, frustrated but learning. I have 2 fuel pumps, a Carter low pressure pump and a cylindrical high pressure pump. Any chance one is failing? Any chance ignition fire is intermittant (I never have a problem while running after starting)? Any value to swapping the ECM's betwene engines? Most likely I need to find mechanic #3 who can pressure test the fuel system? Any other ideas?

Thanks for the help.
 
I'd still validate the spark occurs when the engine won't start...could be an electrical intermittent driven by temp increase. You really have to be methodical in the troubleshooting or you'll literally piss away a lot of money and time.

Same for validaing fuel pressure. If it isn't sufficient, the injectors may provide fuel but not properly atomized, etc.

Another item that would be handy would be a scan tool so you can check the sensors that let the ECU know how to deliver fuel. You want a good tool, not just a "code reader", as a good tool will show you what the sensor's "output" is in human terms. A common hot restart problem is the ECt sensor. Engine Coolant Temp - provides a resistance that changes with temperature. They frequently "fail" providing a legitimate but wrong value. Here's the typical example from the GM ECU manual, paraphased: The engine is at 150 degrees, the ECT provides a value that says 50 deg. The computer selects a 'rich' mixture as it thinks the engine is cold. Engine won't start due to rich mixture. A trouble code never sets because the 50 deg is in the 'legal' (expected) temp range.

Most GM products use the same sensors so getting a non-scan tool method of checking is pretty easy. Just takes much more time than reading them all off the display of a good scan tool. The resistance across the ECT terminals, with the wire connector unplugged, will range from 450 ohms at 160 deg (F) up to ~ 3400 ohms at 70 deg (F).

I doubt swapping ECU's will help; that said, it won't hurt. Just make sure to disconnect the batteries BEFORE unplugging anything on the ECUs.
 
Thanks so much for your feedback.

The weather has been cooler and I have had some hard restarts but no "no restarts".

To follow your advice I have checked the timing and it is correct. To do this I purchased a Rinda code reader which also sets the engine for "base" timing. I know you said get a good analyser but I am trying to take this in a logical progression.

While I bought i to check the timing it is also a code reader soooo ... I had to see what it found. It is indicating a MAP sensor code fault 33. I must be closing in on this problem.

What would you advise for next step? I am amazed that no mechanic has checked this yet.
Thanks for your patient responses MakoMark.
 
The RINDA tools are excellent...don't think you can get much better.

The MAP fault is a very possible root cause. What you need to do is verify the harness and connectors are OK and then you check the sensor itself. Connector/harness problems can be intermittent or constant. A quick way is to use the other engine to get a baseline with the scan tool. Some guys would also just swap the MAP sensors and see if the issue follows the sensor.

That vintage should have 3 pins in the connector: a +5VDC reference from the ECU, a ground reference from the ECU, and the sensor's output.

The last item that comes to mind is to check the hose between the sensor and the intake...If it cracks/breaks/gets disconnected, it will drive the computer to the wrong part of the fuel curve.

another option is to just unplug it. the ECU will use a 'default' value and the engine should run OK but won't deliver full power.
 
After a winter of no restart problems I thought that purchasing only non-ethanol fuel and using Sta-Bil did the trick.
Unfortunately that was not the case. It started acting up again when the temperature rose.
I did find a great mechanic on lake Lanier who confirmed fire, no fault codes and who suspected the fuel pump.
There was no Schrader valve to hook to but he found some bad wiring crimp connectors to the fuel pump.
That did not fix it either but i did find that if I poured ice water on the fuel pump when the problem occured it would restart!
Mechanic said that the electric fuel pumps have aluminum vanes and if the pump was replaced without being primed it might have overheated.
New fuel pump on order and hopefully we have found the source of the problem.
I tried to order the pump from Marineengine.com becuase of the help from this forum but they do not stock it.
Apparently it is a special pump even though it looks like the standard Crusader pump with the two fittings on one end.
Makes me also wonder if the pump was replaced with an incorrect pump (I know it is not original).

I will update this thread if that solves the problem. Thanks.
 
DriftnDrink,

I hope you were able to resolve your problem. Do you have an update?
I am having a similar problem with my new 8.1L marine power engine. It starts okay, runs good, but will not easily restart when it is warm. I can start it by moving the throttle to about halfway and cranking it. It starts at a high idle and I have to immediately pull back. It runs okay after that, but sometimes idles a little unsteady, and even stalls when I'm docking. Not exactly what you would expect from a $13K motor.
My mechanic has ruled out vapor lock as the probable cause. He has been working with someone at marine power, and they are focussing on the ECM and the program. The replaced the ECM, and have updated the program a few times, to no avail. My mechanic has the software to help them diagnose. He runs the engine with a laptop connected and sends the data right to marine power. They review it, tweak the program, send it back, and we load it up. No fix yet. My next step is to have marine power send a rep up to look at it, but they are still trying to fix it remotely. We'll see if they are really reputable and honor their warranty by sending a factory rep to help diagnose and fix this.

If anyone has any ideas on what could be causing my problems, I would appreciate the advice.
 
Hi ctboat ...

We have replaced the high pressure fuel pump and that has resolved the problem.
I have had no issues with this motor starting when cold and running for hours.
But when I shut it off I could not get a restart when the motor was hot until many hours later and it had cooled down.
Try doing what I did ... pour cold water on the fuel pump when it is hot and see if this helps the restart problem.
If it is a fuel pump issue it will not show up on diagnostics (I don't think).
The only way to properly test this is to hook up a fuel pressure guage when it is hot and see if the pressure is correct.
My mechanic wanted to do this but my marine power engine did not have a Schrader (sp?) valve for him to hook to.
In the menatime we got it fixed.
Hope this helps you - I know very well how frustrating it can be.
 
DriftnDrink ,
Thanks for the reply. You're right...this has been very frustrating.
My engine does have the schrader valve and I think the pressure checked out okay at all temperatures.
I also did hear about pouring water on the pump, I tried it, but no change. I'm not sure if I was pouring it on the right part of the pump or if I was using enough water. It is pretty tight in that corner of the engine. This was supposed to be a way to confirm vapor lock, which my mechanic swears is not the problem.
I will talk to my mechanic, and ask him to look into the possibility of a bad pump.

Thanks again, and I'll keep you posted.
Enjoy the boating season...it doesn't last long enough!!
 
Hello everybody, I been having the same problem on starboard engine after it sits for 12 hrs or days starts and runs fine but when I go out and stop for 4 or 5 hrs is really hard to start have to try several times and some times runs for a minute and shuts down and does this until finally starts and then runs fine at all speeds untill you turn it off for lees than 12 hrs by the way this is a 1994 Main ship sedan bridge with 320 hrs on twin 454's EFI with TBI so far it has new dist cap and rotor and fuel filters (whichn it needed anyway)* have swiched the ECM and ignition module from the other engine and checked coil, fuel pressure is 20 psi is this correct for this engines? I haven't been able to find specs on this as yet, when trying to start seems to have spark and spray coming out of the injectors but still no go. I'll try couple of the sugestions on this thread but Ill appreciate any other input
*
Thanks
*
life is short, boating season is shorter so go out and enjoy!
 
I have a 1994 Luhrs 320 convertible with twin 454 Marine Powers and have had same problem and determined it to be vapor lock which a lot of people don't believe because engines are fuel injected. Do you have a generator? I had my generator removed to have rebuilt and that's when problem developed. Fuel line to generator was plugged but when outside temp was hot it seems like vapor was feeding back thru plugged fuel line and causing problem. I installed a fuel cut off switch at the tank feeding the generator fuel line and have no problem. I have had the generator since rebuilt but if not in use I keep the shut off valve off to stop any fuel or air from building up in generator fuel line. Let me know how you make out
 
I have a 1994 Luhrs 320 convertible with twin 454 Marine Powers and have had same problem and determined it to be vapor lock which a lot of people don't believe because engines are fuel injected. Do you have a generator? I had my generator removed to have rebuilt and that's when problem developed. Fuel line to generator was plugged but when outside temp was hot it seems like vapor was feeding back thru plugged fuel line and causing problem. I installed a fuel cut off switch at the tank feeding the generator fuel line and have no problem. I have had the generator since rebuilt but if not in use I keep the shut off valve off to stop any fuel or air from building up in generator fuel line. Let me know how you make out
 
I have replaced the fuel pump, both filters, connected fuel line directly from the tank to the pump and seemed to work so replaced the bracket that holds the fuel filter/water separator and it seems that worked ok but now is acting up again except it seems to start after couple of hours but very hard to start after a day or longer it feels to me that I'm loosing pressure somewhere it keeps screaming vapor lock but is efi with tbi I'm I missing something? once it starts seems to run fine at all speeds.
 
oh by the way the generator works fine I used it a couple of hours over the weekend so I don't beleive I have a restriction on the fuel line but I'll check thanks for your input
 
If it doesn't start after a day or longer it doesn't sound like vapor lock to me. The problem I had was only when engines and outside temp was hot. I also have the EFI and TBI. Maybe something in the ignition, spark plugs, coil, distributor cap, rotar? When was last time engines were tuned? Are you using the correct spark plugs and is timing correct?
 
Thanks for the reply, yes all those items have been checked and if you check on the other comments further up on this thread the problem now seems that has reversed, before when you shut off the engines from 1 to say 6 hrs it was really hard to start but if you let ot sit overnight it started fine now is going the other way starts fine after couple hrs but really hard next day, go figure! it also has new dist cap and rotor and coil checked ok changed map sensor, tbi's and main module from one side to the other and still have the same problem
 
I think I found the problem the culprit seems to be the anti-siphon valve at the gas thank I replaced it and so far is running like a top it was stuck open and gas was flowing back into the tank
 
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