Johnson 30hp runs poor

[13ftwhaler]

I recently decided to fix up an '87 Johnson 30 electric start outboard to use on my whaler. I wanted to make sure it was worth fixing up. I did a compression test. It has 100 psi in both cyl. Electric start cranks it too slow to start, but it will start right up with pull start. It has good water stream from tell tale. wont idle even after warming up for 30 mins. wants to cut out if reved above 1/2 throttle. one spark plug looks black and wet with oil while one looks clean and new. water in one cylinder?

what i want to know is if you think this is carb issue? or possible head or exhaust gasket? or if i just need to decarb?

havent been able to test on the water because im still in process of restoring my '68 whaler

any knowledge would be helpful

 

[tashasdaddy]

Re: Johnson 30hp runs poor

90% of starter problems are bad connections. remove and clean both ends of the battery cables, so that they are shiney, also the cable from the solenoid to starter. check for nicks in the cables. and make sure the connectors are on the wire good. the cable tend to corrode from the inside out, if nicked, corroded wires, and connections, heat up and cause resistance to the follow of electricity, thus the starter doesn't get enough. you can also take jumper cable pos battery post to large post on starter. with a good connection, the engine should spin. then if the starter is good clean everything and retest. then trouble shoot solenoid. starters can be rebuit at a starter/alternator shop, much cheaper than a new one.

also have the battery load tested at the auto parts store, free, i've had new batteries go bad


suggest carb cleaning and rebuild kit, and linc n sinc, see the TOP SECRET FILE. 1st thread in this forum.

 

[Mas]

Re: Johnson 30hp runs poor

Yes, completely go through the carb. If the motor has been sitting, the carb is likely gummed up and causing your problems. Make sure you use compressed air to blow through all the passages and chase with a very fine wire.

MAS