1950s Evinrude 7.5 hp

[mgsolakis]

I’ve got a 1950s Evinrude 7.5 hp and I tested compression today and it’s even at just over 60PSI according to my gauge. Does that sound ok?

[fleetwin]

Well, kind of a marginal reading, but that may just be due to gage inaccuracies or a dry engine. I would attempt to get the engine running then retest. 75PSI is a normal reading for these engines.

[Doug Wilson]

that is about what my 5.5hp tested after setting many years but it seems to be running great anyway

Doug

how is it motors multiply when the garage lights get
turned off?

[20mercman]

Well, I am fairly fond of our 1950 Fleetwin. We converted it to modern coils, as the originals were melted as they almost always are. After that, and some other work and an impellor, it is a very nice motor. Our 53 is back on the rack for now as I am frustrated with trying to solve a vibration problem.

Steve

[wedgie]

quote 20mercman:

Well, I am fairly fond of our 1950 Fleetwin. We converted it to modern coils, as the originals were melted as they almost always are. After that, and some other work and an impellor, it is a very nice motor. Our 53 is back on the rack for now as I am frustrated with trying to solve a

quote :

vibration problem.

Steve

What are your symptoms ? My ’54 rattled until I shimmed the front starter hold down screws.

Sorry to hijack this thread 🙄

60 psi is pretty low. The numbers might come up with a de-carbon, or with a 50 cent hone job.

[20mercman]

It idles and runs fine at slow speed, above half throttle, it starts to shake, and any more throttle and shakes so bad that you can’t run it. It has a brand new crank from Chinewalker, +.020 over bore and rebuilt ignition system. I was planning to swap the lower unit to rule that out, just have not gotten around to it. I am afraid I have a balance problem in the powerhead.

Steve

[mgsolakis]

Would a 50 cent hone job not require oversized rings a well?

[20mercman]

quote mgsolakis:

Would a 50 cent hone job not require oversized rings a well?

Is this question about whether it has the correct pistons and rings? If so, yes, it has the correct oversize parts.

Steve

[fleetwin]

A fifty cent hone job is just that! Nothing more than taking a little fine emery to the cylinder walls to rough them up without removing pistons/rings, etc. Simply blow out any left over dust with compressed air/brake clean. No oversize pistons/rings required, just 50 cents worth of emery!

[1946zephyr]

quote 20mercman:

It idles and runs fine at slow speed, above half throttle, it starts to shake, and any more throttle and shakes so bad that you can’t run it. It has a brand new crank from Chinewalker, +.020 over bore and rebuilt ignition system. I was planning to swap the lower unit to rule that out, just have not gotten around to it. I am afraid I have a balance problem in the powerhead.

Steve

I would try a different flywheel. If that doesn’t solve it, then the drive shaft and components below it should be checked

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