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1976 Johnson 70 hp wonbt get up to speed plane

A

art

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" Just got this 1976(?&#41

" Just got this 1976(?) Johnson 70hp, model # 70ESL75P with the same problems that I've seen posted here recently, namely not able to plane/come up to speed, etc. She will not rev over 2000 in the water, but in the driveway (with earmuffs, of course), she revved over 3000, and likely would have gone higher, but I got nervous at that point and eased it back. Previous replies to this problem suggested a compression test, which I did today (120 lbs in all three cylinders).

What do I do now? Please help. Motors are not my strong point, so please take it slowly. Thanks in advance. "
 
" Hope your running this motor

" Hope your running this motor in water or with a hose connected to the water intake !!
I have a simular motor and never had the problem your describing. I know the plugs like to foul out quite often and I replace them every other use of the motor for reassurance measures, it is worth the few dollars to have fresh plugs and gapped properly @ .030 . I'm no expert and don't take my advice, but sounds like a lose of spark with higher rpm's. such as weak coil's' , worn points, etc.
good luck ! "
 
"Art.... Compression sounds go

"Art.... Compression sounds good. Now, with the s/plugs removed, check the spark which should jump a 7/16" gap with a strong blue lightning like flame..... a real strong wide snap!

If the spark is okay, in all probability the carburetors are fouled. If so, the cure would be to remove, clean, and rebuild them.

S/Plugs should be Champion QL77JC4 plugs, gapped at .040 .

Joe
"
 
That motor should have a 13 1

That motor should have a 13 1/4 X 17 pitch prop. More than likely the problem is fouled plugs. My '78 Johnson 70HP did the same thing a couple of years ago. After 3 fresh carb kits and a thorough cleaning it ran like a dream.

Kevin
 
" Thank you all for your sugge

" Thank you all for your suggestions. I can tell you this - the plugs look almost new and appear to get proper spark, so it looks like the carb(s) may be the problem. So - how many carbs does this motor have, anyway? And what should I expect to pay to have them cleaned/re-built? (I doubt this is something I can do myself). "
 
" Update: It turns out that th

" Update: It turns out that the spark I thought was OK may not be. With advice from a friend, I tested the spark again and while there definitely was a spark jumping from the plug to the engine block over a half inch or so, there was also very small but noticeable spark where one of the smaller orange-colored wires exited the bottom of what I've been told are the coils - and also where the large black wire leading to plug #2 exited the coil. I assume this is a problem that needs to be fixed. How does one fix this? "
 
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