Not sure if I'm in the right msg board, but there used to be one regarding boats and automobiles. Anyway I'm working on my outboard motor and have several questions or rather looking for adice on how to go about trouble shooting and repairing it. If I'm in the wrong board please advise me on where to go. THANKS

Since this is the only place for boating questions I'd guess this is the one.
Not many people around here any more but give it a try.
What's the question?

If this is the right board for the questions about boating then here is the query, my outboard motor is not functioning or malfunctioning, i dunno what is wrong with it?

For one thing you just added onto someone elses post, When posting you need to add your own so there's no confusion who were talking to when someone replys.
Your going to have to be clearer on your question. You say your motors not funtioning or malfunctioning.
Ok which one is it.
Is it not starting, runs rough or what?
What brand and model is the motor.
How long has it been since it was last started?
Is there old gas in the tank?

Not many people have been around this area for a while but post your questions and see what happens, there really is no other good place to post them on these boards.

The question I have regarding my outboard motor is:

I am getting ready to do a cylinder compression test and someone said the motor has to be warmed up prior to performing the test. Someone else said the motor should be cold. Which is it? The motor is a 2cylinder,1978, 6HP johnson.

don't know about 2-cylinders, but in general compression tests are run cold, because you ahve to back out the plugs to do 'em, and removing/inserting plugs hot makes it more likely to strip the threads. small marine engines are all aluminum, more easily damaged.

on 2-cylinders, remember that you usually have a "valve sheet" containing reed valves that flap in and out as the piston goes up and down. they're pretty loosey-goosey to start with. instead of 4 stages per power stroke (input, compression, power, exhaust) on a 4-cycle engine and real valves that should not leak, a 2-cycle draws fuel/air mix with lubricating oil at the same time the power stroke has just pushed the piston down... exhaust and compression are the same upstroke.

so things mix across the lines. huge gobs of oil behind the engine in the water and lots of blue smoke are a good sign you have a bad block or rings and poor piston sealing. you don't need temperature X to find that with a gauge. with reed valves, there is either back pressure or there is not, so the test is a pretty rough test IMPHO. protect the block, spray the plug thread area well with penetrating oil before removing, and work the test cold.

heck, that's only a one-popper, right? either you bounce the needle when you pull the rope or you don't. if not, replace the valve sheet, and use new gaskets.

Thanks for the info. I really do appreciate it.

This post is really helpful for me. I also have a boat and facing same problem.



mercruiser

This message has been edited. Last edited by: Alexa Kelly,