Starting Issues...

[coolgator]

I have a 1977 Johnson 70hp outboard motor. The problem I am having is before I head out to the lake, I always*start*the engine and fire it up prior to putting it in the water (It starts and sounds & runs great). No sooner*I'll put it in the water*the problem starts.....It backfires, sputters, runs for a few seconds/shuts off. It takes about 5 mins before it idles enough where*I am able for me to put it gear and take off....Once I get moving on the lake it runs like a champ. But once you shut it off for about 15 mins, the troubles*starts all over again....

Does anyone have suggestions or may know what the issue is.

Thanks,
Coolgator
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[racerone]

Cosidering it is a 34 year old motor, you should post the results of a compression test!

 

[coolgator]

I am getting 125 on all 3 cylinders

 

[racerone]

If you have spark that will jump a gap of 7/16" on all 3 then clean the carburetors, usually no parts required.