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1970 Johnson 95 Question

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chemrat

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"I have a 1970 9.5 engine that

"I have a 1970 9.5 engine that was running perfectly, then suddenly started to die off. The little engine will sputter, then spit, like a back-fire, a few times, then when I try to throttle,or choke, or whatever, it just dies on off.Sometimes it will crank back up, other times it acts like it's flooded. I can wait a little while and it will usually crank back up, then go into the sequence again.

I can crank it and it runs fine in a barrel at home,naturally, but as soon as I put it in the lake, it starts, then dies off again. Carb was rebuilt in early spring of this year. Where shoud I begin to look for the problem?"
 
"Do the spark plugs look alike

"Do the spark plugs look alike or do they appear different? Describe them. The spark plugs should be Champion J4C or J6C plugs, gapped at .030 . The J6C may give a slight edge in performance.

What is the compression readings of the cylinders?

With the apark plugs removed, the spark should jump a 1/4" gap on that model with a strong blue lightning like flame. Does it.

Note... Making a spark test by using the spark plugs is a waste of time. The gap is crucial.

(Spark Tester - Home Made)
(J. Reeves)

A spark tester can be made with a piece of 1x4 or 1x6, drive a few finishing nails through it, then bend the pointed ends at a right angle. You can then adjust the gap by simply twisting the nail(s). Solder a spark plug wire to one which you can connect to the spark plug boots, and a ground wire of some kind to the other to connect to the powerhead somewhere. Use small alligator clips on the other end of the wires to connect to ground and to the spark plug connector that exists inside of the rubber plug boot.

Using the above, one could easily build a spark tester whereas they could connect 2, 4, 6, or 8 cylinders all at one time. The ground nail being straight up, the others being bent, aimed at the ground nail. A typical 4 cylinder tester follows:


..........X1..........X2

.................X..(grd)

..........X3..........X4

http://stores.ebay.com/Evinrude-Johnson-Outboard-Parts-etc?refid=store

Leave the lines attached to the fuel pump but remove the retaining screws that attach it to the powerhead, then install nuts to those two screws and tighten them so that the fuel pump is secured together.

Now, pump the fuel primer bulb up hard. If any fuel leaks out the back of the fuel pump, the diaphram is broken, in which case, replace the fuel pump.

Let us know what you find."
 
"These engines sometimes leak

"These engines sometimes leak exhaust under the cover and the carburetor sucks it in and this can cause a problem....If the engine will only run when the cover is removed, this could be the problem"
 
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