1974 Johnson Seahorse-no power/high speed

[BlacK_Blade]

I cleaned carb and put it all on..have the basic settings for the high and low speed (.75 & 1.5 turns out)and she starts and idles good, but when I go to full throttle get a slight increase in rpm/power but nowhere close to its full potential.

I have had it out on the lake and fiddled with every possible setting and nothing gets it to improve. Should I check for proper compression? BTW what would be good compression readings for it

Im an automotive tech, and have compression testers, a pc based scope even if that would help in any way..it doesn't have a DLC so can't hook up the scanner

Any suggestions appreciated

 

[racerone]

2 hp or what model #----------Check compression and check spark if it is the 2 cylinder 4 hp motor.--------Spark must jump a gap of 1/4" or more to be considered good on these motors.

 

[F_R]

You can just about bet it is running on one cylinder. Can be compression, spark, reeds, ruptured fuel pump diaphragm, water in cylinder----But not the carburetor. Carburetor feeds both cylinders.

 

[BlacK_Blade]

2 hp or what model #----------Check compression and check spark if it is the 2 cylinder 4 hp motor.--------Spark must jump a gap of 1/4" or more to be considered good on these motors.

Sorry was thinking it in my head but apparently not typing it..lol. Its a 4 hp, with the weedless prop. There is no model # on it anywheres. It is a 2 cylinder. I don't have a service manual for it, tough without knowing the model #. The spark tester I have is stupid and won't fit into the boot...not long enough, been just holding it against the head.

 

[racerone]

Holding a plug against the head is a waste of time.----Does spark jump a gap of 1/4" , yes or no ?

 

[F_R]

As an auto tech, you certainly know it can be as simple as a bad spark plug.

If it is 1976 or older, it has the OMC Universal Magneto ignition system. About 10 jillion of them made, and they are everywhere. Simple and reliable.

 

[BlacK_Blade]

I dug out my spark tester with the adjustable gap (rarely use it at work so was buried deep..lol) Turns out I indeed have no spark on the lower cylinder. I had replaced the coil on the other cylinder last year so now its the other ones turn. Ohmed the secondary of the coil and she was open. Will have to wait a bit until get a few bucks to spare. Sucks that both this motor ended up with a coil issue as well as my other little 2hp Rude, only in its case, the coil is no longer available and only place to get it is ebay. Its a 93 with an obsolete coil, while the old 74 has all kinds of parts..go figure.