If it is carburetored you need to check and ensure the choke is working. Whenever the engine is cool the choke plate should close off. The choke may be electrically heated or heated through a tube. As the engine warms up the choke plate will open and allow normal engine operation. The choke is usually a 2 inch diameter black plastic puck on the side of the carburetor with a bi-metallic spring inside that moves the choke plate as it heats and cools. Let us know what you find!

 

So what exactly do I check? I can get to the carborator without a problem. what do I need to look at to make sure it is working right? If it isn't working right, what do I do to fix it? Take it off and rebuild it or do I spray it with carb cleaner and hope for the best? Also, what do I need to do to properly start the boat so it doesn't stall on me. Should I pump the throttle and turn the key or should I just leave the throttle where it is to get it started and then rev it up a bit once it starts or push it all the way forward and then throttle back when it starts?

 

If the engine is cold, the choke plate should be closed via the action of the bi-metallic spring inside the black puck. If it's not working make sure nothing is binding. You'll probably have to replace the choke housing (black puck) if it won't pull the choke closed. If the boat is cold and hasn't been started in a few days I pump the throttle about 3 times and then crank it. Experiment with yours. This gives it extra gas from the accelerator pump and allows the choke to close. I generally don't move the throttle while starting it and it runs at idle speed after it starts. The closed choke enriches the fuel mixture to keep it running and then slowly opens as the engine warms up allowing the fuel mixture to go to normal.

 

Are you carb or EFI? "EFI" is technically TBI which is Throttle Body Injection which looks kinda like a carb. Do you have this setup?

 

I believe it is carburated. i have nothing on my boat engine that says EFI or TBI and there is what appears to be a carborator on the motor. How do you know if it is a TBI as opposed to a carb?

 

I believe it is carburated. i have nothing on my boat engine that says EFI or TBI and there is what appears to be a carborator on the motor. How do you know if it is a TBI as opposed to a carb?

A TBI will have an injector pod on top, usually with two injectors, that have wires connected to them. Carbs don't have wires on top.

 

Dick gave you good info to troubleshoot your choke and I agree that is most likely your problem. On my carbureted boat, I usually push in the button on the throttle to disengage the shifter and move the throttle to full, then back to neutral. Then I do it again, and leave it at the 1/2 throttle position. The first full throttle stroke sets the choke (you can go look at the carb and see that the choke should be closed) and the 1/2 throttle position helps in starting the engine. Once started, I bring the throttle back slowly to aim for around 1200-1500 or so RPM. It will build over time as the engine warms (and the choke slowly opens). Eventually I can idle the throttle and the engine will idle nicely. Usually takes a couple of minutes and then I feel confident to move the boat away from the dock.

When you stall your engine after having it briefly running, it is hard to get re-started. This is because the choke is still somewhat closed and you'll be then flooding the engine. So if you stall it and it won't immediately fire back up, move your throttle to full. Then re-start. Be ready to pull the throttle back as soon as she fires. This will allow more air to enter the system and cure the flooded condition.

If you do determine that your choke is at issue that are two screws on it that can be slightly loosened and the black plastic cover can be slightly rotated one direction or the other and tried again. However, move it very little and then let the engine completely cool and start from the beginning to see how it runs. It's a slow process to perfect.

Tom

 

Those are great directoions Tom, I know ever boat has its quirks and I'll try that from now on. If I have any problems, I'll let you know. I am having problems with run on with the engine and I'm thinking about putting new plugs/plug wires in. Do I have to replace the distributor car and points with this one the way I did with my 1988 Sea Ray 3.0 liter? I didn't do it, I had a mechanic do it but I just want to know what I'm in for and is there anything else I can do to stop the run on minus the tune up?

 

Those are great directoions Tom, I know ever boat has its quirks and I'll try that from now on. If I have any problems, I'll let you know. I am having problems with run on with the engine

Ha! My 3.0l has the run-on issue too. There was the equivalent of the Technical Service Bulletin issues years ago about it for my engine. Basically it said to switch to a "colder" set of plugs. I didn't do that as that would seem to mean less efficient. Anyway, the real key is to get the idle to spec. The run-on commonly happens when the idle is too high and when the engine is hot from just running on plane. So get your idle speed set and then after running the boat for awhile come down to idle speed, let it run for a minute or so, then kill the ignition. That works for me.

 

Your boat shouldn't have points. It most likely has solid state ignition. I would be very surprised to find your 88 had points also. Should just have a cap and rotor.

 

The old one had points, either that or the mechanic lied to me and told me he replaced them. When I replce the plugs and the wires, what else needs to be replaced to get rid of the run on?

 

Wow. I am pretty sure they quite putting points in cars after the 70's. Boat builders have always tended to hold on to old technology longer than autos, but that surprises me. I had an 89 Taurus SHO that had a distributerless igniton. Anyway...

Run-on, or diesling as I have always heard it, is usually either a timing problem or cylinders with lots of carbon buildup. Check the timing.

 

All good advice, but we still don't know what you have, fuel injection or a carb. Take several pictures and post them. Once we know for sure what you have we can give sound advice.

 

Agree, but with his symptoms and being a '97, gotta be a carbureted engine.

 

Please don't take this wrong. If you don't know if your looking at fuel injection or a carb I would
advise against YOU rebuilding a carb. There is more to it than changing gaskets and you can
rebuild more problems into the carb than you started with.

Run on is caused by detonation, I would advise you go to colder heat range plugs ASAP.
If you want to destroy a good engine let it detonate.

Cold start you need the choke plate closed as the others have said. If it doesn't do it's
job then you'll have to "pump the gas to get it running again". The acc pump replaces
the gas the choke plate "would" have allowed into the engine for start up.

If the choke isn't working and you just crank the starter not much is going to happen
but ruining a good starter.

The answers are in the posts above, you just need to figure out what you have so you
know which to apply.

A few pictures would really help nail this down for you.

Hang in there.

 

I have a 5.7L with carb your starting issues like others have said is correct I always pump it 1 time with neautral button in then bring it back to 1/4 throttle after it starts let it run at 1200 to 1500 rpm as it warms up rpm's will climb watch it it will rise fast as it warms up to around 2000rpm or more bring throttle back to neautral. We purchased some old fuel 80 gallons that caused some detonation I checked everything points, cap and timing all was good put 2 bottles of Lucas octane boost in it solved the problem. Old gas looses octane you never know how long gas has been sitting in the marinas tanks I always add 1 or 2 bottles of octane boost now nomore detonation problems.