Boat motor tune-up?

Question

I have a 1987 40hp Johnson tiller drive motor. I just got it last year and don't know much about boat motors. Can anyone tell me what would be involved in tuning it up? It is running a little sluggish. Thanks!

Answer 1

Hi there

The normal procedure for my shop is as follows. We do a compression test which will tell you the condition of your moter.If you have a variance of more than 15 psi.between cylinders you will have running issues. We then do a spark test which gives you a good indication of the shape your ignition system is in by the color of the spark. You are looking for a pretty blue spark. We then change the gear oil and look for water in the gearcase as well as any metal shavings indicating gear wear. After these things we install new spark plugs,gear oil and grease all grease fittings and put motor in test tank go through the synchronization and timing and carb. adjustments and run the motor checking the waterpump output and running of motor.This is the recomended procedure we go through in my shop. Hope this helps you out.

Answer 2

Plugs, fuel filter. air filter and oil change

Answer 3

also get a can of Sea Foam and add it to the gas.

Answer 4

Minor tune would involve new plugs, a fuel filter. the carb might need a slight adjustment. From what you described it might be a little rich and need to be leaned out which can be done while the motor is underway. Take care not to lean it out to much as it won't idle well and can be hard to start. Also I would clean the fuel pickup screen in your gas tank as they tend to load up with crud over the years. check your squeeze bulb for cracks and leaks also.