HELP!!!! Engine will not plane

bystorm · May 29, 2004

I have a 1983 150 V6 Johnson Seahorse. Recently my father-in-law took my boat out and ran all of the gas out the boat and drain the battery while attempting to start the engine again using the reserved tank in the boat. After getting towed in and replacing the battery, the boat has not run the same since. At first it would just take a little longer to plane but now it will not plane at all. I took the boat to a local shop and they clean and soak the carbs and jets but I am still having the same probelm. The engine seems to max out only at about 3000 RPM. The compression readings for the engine are: 2 = 80 1 = 80 4 = 85 3 = 90 6 = 75 5 = 85 Does anyone have any suggestions on where to look next to help solve this issue?

R.Johnson · May 29, 2004

Re: HELP!!!! Engine will not plane

Do an ignition test to make sure you have good spark. In this case I would do a running test, not just a cranking test of the system. Do a fuel test by spraying mixed fuel into the carb throats with a squeeze bottle, or by hitting the choke while trying to plane. If this don't find the problem, I would pull the cylinder heads starting with that left bank.

bystorm · Jun 4, 2004

Re: HELP!!!! Engine will not plane

Thanks R. Johnson. I got the mechanic to check the spark this week and he found that it had two damage coils. He is in the process of replacing them now and I should be able to see if this fixes the problem by the end of the day today. You saved me a lot of money...the last guy I went to said that he wanted to to a complete rebuild that would run me about $1500. Thus far I have only spent $65. Thanks again.

LubeDude · Jun 4, 2004

Re: HELP!!!! Engine will not plane

Providing your guage is correct, those numbers, (although close to each other), seam very low. You probably need a very good decarb, that might bring the numbers up some.

bystorm · Jun 4, 2004

Re: HELP!!!! Engine will not plane

Just came from the water and the coils that the mechanic replaced in the boat didn't help at all. When I talked to him over the phone he said that he replaced the coils with some used ones that he had in his shop and I was wondering if those could be bad also. As far as the compression being low..it has had the same readings for all long as I can remember. As mention before I have had the carbs clean so I don't think a really good decarb will help at this point. I was wondering if anyone thought that my problem could be the power pack.

LubeDude · Jun 4, 2004

Re: HELP!!!! Engine will not plane

A Decarb has nothing to do with the carbs, it cleans the carbon from the inside of the engine and around the ring packs, Its a necesary thing to do every year or two. Like this guy says. web page

Solittle · Jun 4, 2004

Re: HELP!!!! Engine will not plane

Have you done as R.Johnson has already suggested - - "Do a fuel test by spraying mixed fuel into the carb throats with a squeeze bottle, or by hitting the choke while trying to plane."??? You started this by describing how your motor ran after running out of fuel. It kinds makes sense to pursue the fuel system a bit before you start throwing parts at your motor & $$$.

bystorm · Jun 4, 2004

Re: HELP!!!! Engine will not plane

I did try to hit the choke today while trying to plane but I didn't get any positive results. The engine would just kind of die down. What is a decarb??

bystorm · Jun 4, 2004

Re: HELP!!!! Engine will not plane

While spraying fuel mixed fuel down the carb throats, what should I look for?

R.Johnson · Jun 4, 2004

Re: HELP!!!! Engine will not plane

If you have a carb that is not delivering fuel, spraying fuel into the carb throat, will make the engine pick in speed , and power. It will also show you which carb is causing the problem. You might also try this! With the engine running, use an insulated pliers, and pull one spark plug lead at a time, and see if you can detect a difference. If you do this on the water, be careful of that spinning flywheel.

bystorm · Jun 5, 2004

Re: HELP!!!! Engine will not plane

And what about the decarb process. Lubdude stated that this was something that I should try but I thinking that when I had the Carbs serviced than it would have took care of this problem. How does the decab process work?

R.Johnson · Jun 5, 2004

Re: HELP!!!! Engine will not plane

Decarbing is done by spraying a cleaner through the carb throat. This product is sold under different names. The only one I have used is sold by OMC and is called Engine Tuner. This product will clean carbon from piston tops' rings', and exhaust ports. The most important being the rings' to keep them from sticking, or getting them unstuck.

LubeDude · Jun 5, 2004

Re: HELP!!!! Engine will not plane

Originally posted by bystorm: And what about the decarb process. Lubdude stated that this was something that I should try but I thinking that when I had the Carbs serviced than it would have took care of this problem. How does the decab process work?

Follow instructions on this link: Decarb

boatin · Jun 5, 2004

Re: HELP!!!! Engine will not plane

Bystorm, Decarbing is not going to solve your problem. Carbon build up in your motor is a gradual process. You need to pursue some of the suggestions other posters have given you. good luck and keep posting

jasper2447 · Jun 15, 2006

Re: HELP!!!! Engine will not plane

Hi there Let's add my two cents worth isn't it possible that the fuel in the reserve tank was very old and had evaporated somewhat - Old fuel does get sticky deposits and there could have been rust / water and heaven knows what in there. That's why a spare fuel tank should always be drained off and refilled at least each season. The symptoms sound to me like partially blocked jets / float valve / water in carb bowl etc. from using degraded fuel. john B

jasper2447 · Jun 15, 2006

Re: HELP!!!! Engine will not plane

Sorry I meant to add - so stop squirting stuff down themn and get the carbs off and stripped and cleaned out thoroughly John

HELP!!!! Engine will not plane

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