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Sea Scouts - S. Florida
12-07-2010, 05:15 PM
Hello,
*
I Skipper a BSA Sea Scout Ship in S. Florida and oversee a fleet of boats for our region's squadron. One recent donation to our organization is a 1997 MAINSHIP 31ft. Sedan Bridge with +/- 370 hrs on the engines. She carries two MarinePower 350EFI.*Would someone shed some light please on the following: Port and Starboard engines both start and idle very well at temp. +/- 150F, cruise temp. +/- 162F. My port engine cuts out after 15-20 mins at cruise 2200rpm. No stutter no cough just dead....! Will not restart immediately but does so after maybe 20 mins. this has happened three times already, we have had a friend mechanic diagnose with a computer and "all readings are per spec" says he. Short of swapping out parts until*I get lucky, any suggestions?*
*
Don't laugh but I recall that my old Dodge Dart*had a failing coil, after heating up she would cut out but *would restart once I cooled the coil with a rag soaked in cold water..... Obviously I do not want to try the same at sea on these fancy engines, but could it be the coil? Anyway to test!
*
All help appreciated
Boys Scouts America
Sea Scout Ship 814
Skipper Furlan
Cell: 954 5514068

robbins29
12-07-2010, 05:50 PM
Check the fuel tank vents to make sure you don't have one clogged by a mud dauber. After that it surely sounds like a temperature-sensitive electrical problem like coil, wire harnass plug, fuel pump.

RicardoMarine
12-08-2010, 10:23 PM
The beauty of twins, is the ability to swap some components.... such as your ignition modules and/or ignition coils, and without too much trouble, and certainly with little expense!
If there is enough fuel line length, a portion of the fuel system can be checked this way also.

It can become part of your P of E.... (process of elimination)... one item, one item only at a time.
The P of E will never let you down if done systematically and thoroughly.

You'll find it, it just may take some fiddling around, and a few test runs.
Good luck.

.

makomark
12-09-2010, 01:00 PM
If each engine has its own fuel tank, I'd start with it. Check the vent per post #2. Two other items can cause these symptoms - dirt in the bottom of the tank blocking the pickup screen and an anti-syphon valve that is malfunctioning.

If both engines 'drink' from the same source, I'd start with the ignition system on the troublesome one, per Rick's post #3.

Sea Scouts - S. Florida
12-10-2010, 09:57 PM
Thanks to you all for the quick response.

I have since tried the engine and again the Port engine cut out at cruise same sit. as before. This time we pulled a spark plug wire and grounded with a screw driver on the block then tumbled the engine,,,,no spark!!!!!!!!

Seems to be electric then and associated to temperature...I am going to descale the engine (with a home made pump and barnacle buster) maybe it is a sensor otherwise I am guessing it is the coil....may either swap starboard to port and test or simply replace the presumably damaged one...

Will let you all know.

Thanks again!

highvoltage
12-31-2010, 12:02 AM
I have a Marine Power GM 5.7L MEFI-4. I have the same exact problem. I replaced the coil with the ICM and it did not solve my problem. I am still working on my issue and believe it is a sensor or the ECM. I have been troubleshooting this for sometime and am about to go to carburation. I am interested to see if you are able to isolate the problem.

Docksidemarineservices
12-31-2010, 08:49 AM
Does the engine have a crank sensor?

highvoltage
12-31-2010, 12:07 PM
Yes it does, and I have not replaced it yet.

Docksidemarineservices
01-01-2011, 10:49 AM
I would check that first.

patillod
02-05-2011, 12:55 AM
any resolution to this problem yet? i have the same issue and would appreaciate any ideas...

Sea Scouts - S. Florida
04-07-2011, 05:24 PM
Sorry for the delay in response. After descaling I was unable to resolve so I opted to change the ECM, the coil and rotor...she ran great at WOT for 20 miles...no probs at all. Then a copule weeks ago she failed again on the Port engine but at idle (would start fine) cuts out after 15 mins....engine is not heating up! I looked below the helm station thinking maybe a loose wire (can't see nor "feel" anything loose) nor is there any eveden oxidation. I then had someone have a look and his opinion is that the fuel is dirty he sees filth in the GEN SET filter that feeds off of the same tank. SO- this sat I am going to top her up with high test and use SYNTEK fuel additive (great stuff), put her to sea I hope to run about 100 miles round trip and that that would clear up any filth in the tank. Boats - or Lord!

makomark
04-11-2011, 03:00 PM
If the fuel and tank are "dirty", best to remove and replace it, especially with the ethanol variable.

"Polishing" fuel has been common for fuel oil installs for a while and is relatively 'new' for gasoline. I'm not conviced there are any OTS chemicals that can 'restore' fuel that is contaminated or degraded.

May also want to get a fuel pressure gauge and a test light to monitor the fuel pump....those pressure control switches seem to have a high failure rate.

Sea Scouts - S. Florida
04-11-2011, 07:34 PM
Folks,

I'll begin by saying thanks to all for response and suggestions. I believe that I have resolved my challenge, following are details:
Last Sat. we put to sea for an intended 100 mile trip we completed 80 miles. Prior to leaving I replaced port engine fuel filter - I neglected to replace Starboard filter due difficult access. I applied 5 oz. XFT (double dose treatment) at fuel top-up. We had 100 gals old fuel some of which was several years old...and 100 gallons fresh fuel 89 Oct. ($5.50/gallon - on the water cost). I carried four spare fuel filters on board for the trip. Result: First leg (At 3000 rpm) at six hrs. starboard engine stuttered and coughed then lost speed then sped up etc. etc. for maybe 3 mins. then shut down. I replaced starboard fuel filter, she stared up immediately and we ran both engines 3000 RPM for a further 2 hrs no problems. Next morning for a further 7 hrs. back to home port. (Engines ran smooth as silk).
I believe that the residue build up (varnish) and other accumulated filth, because I ran her long and hard, and with the movement at sea - was pulled into the filter to the point of starving the starboard engine. I will again replace both filters and once more top up, I expect only good things!
I am happy to give details on the product if needed.

Again thanks for the assistance

Sea Scouts - S. Florida
04-11-2011, 07:35 PM
Please have a look at the note below, i have I believe finally resolved the issue. let me know if you want to try the same product!