Trojan F36 Port Motor Starting Problem

[fdean396]

For about a year I've been experiencing a recurring problem with my port motor. After running the motor for an hour or more it won't restart after being shut down for around a half hour or longer. Sometimes I can get the motor restarted but when is does start it dies once I put the motor in gear and travel 100 yards and then I can't get it to start again. Each time this happens I have to return my boat slip on the starboard motor only. A couple of times I got the motor restarted right before we docked the boat but that has not been the case recently. If I can't get the motor restarted the next day the motor starts, runs great but the same problem happens all over again under the same conditions. Initially we replaced the distributor cap, rotor, coil and spark plug wires but that didn't fix the problem. A couple months ago we installed a new distributor, coil and starting module. That didn't fix the problem. A couple days ago we installed another new coil and starting module and we're going to take the boat out today to see what happens running and shutting down the boat under the same conditions. My mechanic said he still believes it's still an electrical problem. If the new coil and starting module don't fix the problem we'll continue checking for other electrical issues and he'll come out on my boat and we'll run it under the same scenario to see if he can see first hand what's happening. I've never had this problem with the starboard motor. The boat has Marine Power 454's with about 900 hours on both motors.

Does anyone have any idea on what's going on and any possible solutions?

Thanks!

[mikeal67]

When was the last time your carburater was rebuilt?

[prowlersfish]

Also look at the main electrical plug in for the engine terminals can get lose or corroded .

[mike0469]

Have you considered the possibility that it is a fuel issue? You may be getting a vapor lock. Since this happens after you shut down the engine; the heat from the engine may be boiling the fuel. Is the fuel line running up against the engine or close to it; may be able to insulate the line and route it further from the motor to test this theory. Also, try to run the engine with an open compartment to let it breath and stay cool while running. Someone mentioned the carb...this could also cause this condition....just other option to check.

[prowlersfish]

Speaking of fuel , check the check valve at the tank if your not getting fuel but ......

Your saying electrical is it cranking ? if so is it getting spark ?

[P-Dogg]

I had similar symptoms which were eventually cured with a new distributor -- started and ran fine when cold and in neutral, but slowed down after a few minutes. You've replaced your distributor, so I also have to think fuel might be the issue.

At my fuel manifold, it is easy to feed either engine from either tank pick-up. If that is the case on your boat, you might try swapping fuel sources and seeing how it goes. At least it is free to try. Might be the anti-siphon valve is partially clogged, leading to reduced pressure in the line over time. Inspect the AS valves carefully. One of my anti-siphon valves had a hairline crack one time.

And is there anything besides air in the clear line that leads from the fuel pump to the carburetor? Please keep us posted. Solutions to solved problems is the most useful part of this forum, if people bother to use the search feature. Good luck.

[captainmaniac]

You said it won't start again if it is shut down for a half hour or longer... but obviously you can get it started again a few days later or you would never get back out of your slip for another run! How long do you have to leave it before you can reliably start it again? And is it easy or difficult to start when you do that?

[Scorpion07]

I had similar symptoms and traced it to a faulty engine synchronizer. Pulled it out of the system and haven't had a problem since. It was the old strobe light style.

[oil&water]

Any chance it is a bad choke spring that is causing the choke plate to not open up? This would be a classic symptom of start when cold and not when hot.

[zedtwentyate]

Any chance it is a bad choke spring that is causing the choke plate to not open up? This would be a classic symptom of start when cold and not when hot.

I was just going to say that! I had a similar issue and it ended up being the choke.

[fdean396]

We took our boat out again yesterday and the same problem happened when we shut down at our dock. At least this time we were at the dock and not trying dock the boat on one motor with a cross wind! That's never fun. Waited about five minutes after shutting down and the motor restarted and seemed to be running fine. Shut down and waited fifteen minutes and tried restarting and motor started but when I throttled it up is was deinately missing at lower RPM and as it ran longer it ran rougher and then it just stopped running. Tried restarting and same problem. Tried starting again and motor cranked but would not start. Pumped the throttle a few times and the motor started, ran very rough and while giving it more throttle there was a loud backfire if the carburetor and the motor died. I did not try starting it again. Every time this happens when I return to the boat the next day the motor starts and runs. Once the motor has fully cooled it always starts and seems to run well until we take the boat out again.

I greatly appreciate all the feedback. My mechanic said the problem could be a vapor lock and the fuel could be boiling off but also thinks it's something electrical. I also think as mentioned in one of reply posts there may be a carburetor problem. I have owned the boat for 13 years and the carb has never been rebuilt. I'll also talk to mechanic about the other electrical and fuel issues mentioned in the posts. I'll be sure to post once we figure out the problem and what fixed It.

This is a great forum! I have received great advise and have learned a lot about our boat.

[mikeal67]

Does the gas you use contain Ethanol , if so I'm thinking your carb needs a rebuild .
I live in an area with ethanol in the gas , Carb rebuilds are common as is the problem you have described .

[fdean396]

Fortunately I run my boat on gas without ethanol. Going to check the carburation and other electrical issue suggestions that were posted.

[fdean396]

My mechanic and I are working on the fuel problem now. The problem happened again last night so we brought the boat into the shop. The same problem happened this morning after running the boat for about a half hr. Port motor starts when cold after last night and runs great. Stop and try restarting it and it starts, runs rough after a couple minutes and eventually dies and won't start. There's no fuel coming in to the carb. There's no vapor lock in the fuel line. Installed new fuel filters and still no fuel. Trying switching fuel sources and still no fuel to carb.

Any other ideas or something we might be missing?

[prowlersfish]

Have changed the fuel filter(s) and water separator ? Don't for get about the small filter in the carb .