Trojan Boat Forum

I have a engine problem that is quite bother some. My 1983 with twin crusader 270's(350 cu in) engines. I bought the boat in early June and live on it a Key West marina and go out on it once or twice a month. Before I moved on I had the boat pulled and a bottom job done, the engines tuned up, plugs, points, cap, rotor, oil changed, fuel filters replaced, hoses replaced, cooling pumps rebuilt ect.. I trust the mechanic that did the work, I was there for most of it and he save all the parts he replaced and gave me the reciepts of the purchased items. On to the problem. Both times that I have gone out on the boat the starboard engine has given me problems. It will only start by giving it quarter throttle and will die when it is brought back to idle. Once it has warmed up at 1100 rpms or so I can bring it back to idle and it runs fine. I can motor out of the marina at idle without a problem. After running for 20-25 min. if I bring the throttle back to idle the engine quits. It will start right back up if I give it more gas and run great at anything above idle. As I am sure you are all aware this makes it very difficult to bring back in to the marina on one engine. I read online that it could be the coil, I swapped coils and the problem still is with the starboard engine. Other than that I have not swapped out anything else.
Any help would be appreciated.

Thanks

Try swapping carbies.

What model boat do you have? I had the same problem with my F-32. Like clockwork the starboard engine would quit after about 20 minutes. I spent a lot of money on the engine mech changing parts, fuel pump, rebuilt carbs, new fuel lines and time after time the starboard engine would quit. The next thing was pumping out all the gas and cleaning the tanks, this seemed to fix it until a month went by and it started up again. We knew it was a gas problem at this point because the starboard engine would run fine on the port tank. Long story short I had water in my starboard tank, the engine would run, then stop, then if you waited it would run again. It turned out that the boat washer guy was spraying water in the vent hole (the boat was starboard side to the dock) and no matter what we did he would just put it back in. I have since put SS clam shells over the vents and the problem is gone.

+1 on Doug's comments.

When the boat is sitting in the slip the water has a chance to settle to the bottom of the tank and come to rest well below the level of the fuel pick up tube.

As you run the boat things get mixed together and would lead to the symptoms you describe if indeed you have water in the tank. Is it possible to run both engines from the port tank as a test? Draining the tank without knowing for sure that water is the cause is pita and probably costly to dispose of any contaminated fuel.

Maybe a temporary in line glass fuel filter that with a large reservoir bowl on it that will show separated gas?

Good luck. We are all hoping you find the culprit and share the news/fix with the rest of us.

Barry

I was thinking it is carb related. It is a 1983 tri-cabin. I'm sure it has been repowered at sometime. It only has a single gas tank, so I had ruled out a fuel/water problem. Since I live aboard I know no water is being sprayed in the engine compartment.

Is it possible for you to have someone at the helm operating the boat while you are in the engine room watching the engine as you run it in all scenarios? If so, you may see the problem.

You may have a choke malfunctioning and if you pull the flame arresters off you can watch the carb, choke, and everything else while it is experiencing the problem. I found a problem just that way on my tri-cabin. It was having a different engine problem, but watching it closely while underway may help you find the problem.

I'm certainly no mechanic but just my 2c

My guts are telling me choke as well. There is an 'idle cam' on the carb that keeps the choke from fully closing at low speed. If the screw that rests against this cam isn't adjusted correctly the choke can close completely at low speeds, which will kill the engine. When the throttle is open enough, the choke is pulled open hiding the real problem.

Once things warm up it runs better, but quits when you slow down from speed. Again, my guts are telling me the choke spring isn't working right, or choke needs adjusted. When you kill the throttle, it's closing too much. When the engine is hot, it should stay wide open regardless or RPMs.

Thanks everyone. Since the starboard engine does start hard I did pull the spark arrester off as it was idleing and the choke was wide open. Did not check it after the engine was hot. Since it is pretty warm(hot) here most of the time I have had the spark arresters off when the engines were not running and the choke was wide open. Not sure if that is what should be happening?

sss

Thanks to all for the recomindations. It turned out to be the screw that adjusts the points had loosened up. Reset the points, tightened the screw, checked the timing. Ran perfectly.

Good deal glad you found it. Pesky problems like that can drive you crazy.