92 mercruiser 3.0 won't start or stay running unless given heavy throttle

[mikwur]

I posted on this topic last week, but thought the cause of the engine cutting out was shift cable. After running again today, realized that the boat is not stalling because I shift into/out of gear, but actually will not start unless I give it consistent, substantial throttle. The boat stalls when I shift into gear because I am no longer giving it gas (while in neutral), not because of the actual shift. I checked shift cables and they look good. I checked the throttle cable and it looks good. I checked the carb and notice that the choke plate sticks open or closed, depending on how I set it. Some feedback I received on the last post directed me to rebuild the carb, I've heard it is fairly straightforward, but have never tackled this project. Appreciate any feedback on experience with this issue and solutions. Thanks.

 

[Rick Stephens]

A very clean carb is the goal. It is not all that hard to disassemble a 2 barrel carburetor, clean and brush and run all the ports to make it perfect clean. Replace all the parts supplied by the kit is the usual best practice. Most kits have more parts than for a single carburetor model. So have to be careful to choose the correct ones. I used to always keep around the chemtool carb dip solution. Comes in couple gallon can with a removable lid. Disassemble the carburetor and drop it in the tank to clean it completely of deposits. Only really need that if the inside is built up with varnish and the like. Elbow grease and carb cleaner with a few brushes and wire chasers is usually enough.

Also check fuel filters. Lots of boats don't even have them and water is a wondrous thing everywhere but in your boat. Doesn't take long for suspended water to plug up a carb. Add a good filter to your boat if it doesn't have one, replace the one it has if it does.

Rick

 

[mikwur]

Thanks Rick. Does it sound like my issue is with the carburetor?

 

[Rick Stephens]

Good place to start. 12 year old boat it certainly can't hurt. How many 12 year old cars don't need the carb gone through to keep it top shape?

 

[Watermann]

When was the last tune up done on the motor? A combination of problems could be at work with the symptom your describing. Fuel delivery problems most often appear as the motor's fuel demand increases and the easy place to start is with the filter for sure. So after you get her underway and run up to WOT what happens during the acceleration?

As far as carb rebuilding goes, I guess it's pretty straight forward for some but if your not the pain staking meticulous type then have someone do the rebuild who does them frequently.

 

[mikwur]

Took the carb off last night and am ordering a rebuild kit. Neighbor has rebuilt several and has the dip, so I will soak it for a day and then rebuild with him. I am looking at kits online, but not completely sure which kit to get. The motor is a 1992 3.0 mercruiser with a 2 barrel carb. number stamped on carb is 9562A-2 and below it, 2102. Which number do I go off? Waterman, to answer you question, a tune was completed a year ago this spring. The boat was gone through and prepared to use, but never put in water. Then, winterized at same marine service center and stored. I had the boat up to throttle two weeks ago and it seemed to move pretty well, albeit a bit sluggish. Although at that point, I had some problems with the prop, keelguard, and trim tab that have since been fixed. I think the majority of my issues in that area were related to the outdrive issues. Once I get the carb rebuilt and replaced, I will start it up on the trailer and then go from there.