My problems started the 4th of July weekend and I am still pulling my hair out over it. Here is what is going on.
I can start the motor and get the boat idling at the docks. While out of gear I can rev the motor to whatever I want to. However if I leave the motor at idle after a few minutes the motor will drop rpms, start to struggle and then die. Before the rpm drops there are no misses or sputters in the engine. I am thinking it is not in the electrics because of the smooth idle before it dies. If there was a bad spark plug or wire I believe there would be a miss at idle. There is no smoke or gas smell out the exhaust that would indicate running rich. I changed the fuel / water separator and it does the same thing.
The engine is a 350 with a holley 4 bbl carb.
I am open for any suggestions as to where to look. I am going over hoses and tank parts today. Does this sound like a pump?
Will it start back up after it dies? does it have oil pressure, hows the water temp? It sounds like the engine is locking up, will it crank at all after it dies?
The engine will fire back up. Sometimes it takes a couple of tries sometimes it is just a turn of the key. The starter is cranking strong. Oil pressure is fine, the temperature does not get hot. There is not water in the oil.
I pulled the anti siphon valve out of it today and put a plain hose barb to try. It ran for about 15 minutes at the docks with no troubles. I had something to eat and then came back to the boat. It was acting the same as before. It would start and then after so long it would sputter out.
We had the same issue, same engine, same carb. The cause turned out to be the brand new spark plug wires from Napa, we replaced with a "higher quality, read higher $" set, and it solved the problem. Found out the hard way, hubby got zapped from one of the wires, then got zapped by another one.
M/V The 69 Queen
1969 River Queen 40'
and a 24' Pontoon "Red Solo Cup"
Port of Fulton, MS
Do I understand you correctly that it only happens while the boat is in gear and it will rev fine when in neutral? What drive do you have? Is there a neutral interrupt switch that may be on the fritz? It also sounds like it could be a carb issue. I'm not as familiar with the Holley marine carb, but on my old Rochester 2bbl, the float began to develop tiny cracks and holes, it finally filled with gas and it no longer floated. Your symptoms are pretty general, it could be lots of things. We can assume you have air and compression. So you need to duplicate the problem and at the same time see what you're losing, spark or gas.
Right now it is happening when the boat is idling out of gear at the docks. I have not tried to put it in gear lately. I don't think it is an interrupt switch because it dies when it just sits there. I get the boat started and let it idle and it will stall out.
Tomorrow after work I am going to try changing the spark plug wires and maybe pull a plug or too and look at them. If I have enough time I might pull the carb off and look at the float. It is a pain to get the carb off the motor. Holley did not do a good design for bolt access.
Just a list of recent years changes. Re-manufactured 350 ci engine 2008. (replaced a 305 with worn out cam shaft and cracked heads). New SEI 106 outdrive (upper and lower units) and new carb in 2009. Also in 2008 new coil and distributor. The distributor has a electronic module (no points or condenser)
I just installed a SEI 106 complete and I can't get the thing to shift right no mater how I adjust it. It's damn near imposible to get it in neutral. I can hear the interrupt switch working. I'm just wondering how yours works? (sorry didn't mean to steal your thread)
I changed the plug wires last night. It looks like that might have been the issue. The boat now starts easier and stays idling. Tonight I will take it out and put it through the tests.
I have not had any problems with the outdrive shifting. It sounds like either the shift cable or interrupt switch needs adjusted. What RPM are you idling at? The lower the better when it comes to shifting.
It sounds like you are in the right idle area. That little nut in the back may need adjusted.
I am back to ground zero. I changed the spark plug wires last night. It idled for 30 minutes without stalling. I go today and it won't stay idling for more than 1 minute. I am confused and frustrated. I am starting to wonder if it is a fuel pump issue? Can anyone recommend a good mechanic in the area? I need to get this fixed.
well you can always go to the parts store get a $12 fuel pump (non marine) just try it before you really shell out the $$ if that is you problem I wouldn't recommend you leave it on. Spend the $150 on a good marine one trust me. It does sound like a fuel problem to me (assuming you have good spark)
It's could be something so small to. does it have a fuel filter after the water separator ?
when my fuel pump died the pressure went from 6psi to 14psi! that really made it run rich.
I changed the fuel water separator already. It did not make a difference.
A guy at work today told me to check the fuel pressure. I did not realize that the pressure may increase if the pump is going bad. It is a mechanical fuel pump. I thought they worked or did not. I need to come up with a way to put a pressure gauge inline after the pump.
I don't want to sound like Mr. Obvious, but you'd be further ahead diagnosing the problem rather than replacing things one after another without knowing the problem. You may eventually replace the right part and fix it, but you may spend a ton of money to get there! Sounds like it's running out of gas. I'd start by making sure you're getting and maintaining fuel flow.
I am trying to eliminate what I can think of. I am asking for possible places to look. Today I tested the fuel pump. It has 5.5 psi at the carb. The only money I spent so far is for a new fuel filter.
Things I have done
removed anti-siphon valve, had no effect
changed plug wires with set I had. Ran good one night at the dock the back to the stalling
changed fuel filter with no effect.
The boat stalls in idle if I let the choke work itself or if I tie the choke all the way open.
My next idea is to remove the brass filter at the carb inlet and maybe change the spark plugs. I am running out of ideas on things to check.
Any suggestions as to what to look at next are appreciated.
That is reconmend from the factory is to remove the filter at the carb. Even Holley reconmends it from the factory on marine applications. All I run and everybody else that I know only runs the spin on filters. Might even be a dirty carb or bad gas. I would pour the cleaner into the tank even pour extra. I would do that first. If it is not fuel related and it will run for a while then start to sputer and stall might even lead me to think once it starts to warm up something is opening electrically. I would assume it is an electronic ign. and if it is a mercruiser the thundervolt is damn near bulletproof.
I could not work on the boat this weekend. I had family in from out of town. Tomorrow after work I will remove the filter, check the plugs and inspect the power valve on the carb.
I have added two cans of seafoam and dry gas already. When I put the new filter in I had seafoam in there too.
Long shot here, but have you checked the tank venting? I don't know the boat or type of tank you have but in some applications, it could be a possibility.
Long shot here, but have you checked the tank venting? I don't know the boat or type of tank you have but in some applications, it could be a possibility.
It appears the problem was a bad power valve in the carb. This then fouled out the plugs. Lots of headaches and lost time for a small part. Thanks for all the thoughts as to where to look.
Engine / Running problems
Reply With Quote
2007 Rinker 246 cc
Originally Posted by nitsuj
