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What is the normal compression on a 1962 Johnson 75 HP

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LowBudget

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" I'm looking at an older

" I'm looking at an older (1962) 17 foot, wide jon boat with console steering. It has the original 4 cylinder 75 HP Johnson Electramatic. All 4 cold cylinders are at either 92 or 93 pounds compression. Is this OK for an older engine? What compression did it probably have when it was new? Short of dissembling/rebuilding, are there any tips or methods to improve it? Thanks to all who respond. "
 
" These motors were smooth run

" These motors were smooth running and rugged.They originally ran at 24:1 and did not have nearly as many problems with pistons and rings as the new er motors. A draw back is fuel consumtion but if you are an occasional boater why spend tousands to save a couple of hundred dollars a year on fuel. The even compression is a good sign , I would run it. "
 
" LowBudget,

I have

" LowBudget,

I have no idea as to what would be typical for that engine, but 90 psi and even really isn't all that bad; if it runs the way you'd like it to, why worry about it? If you don't allready own it, you may want to think twice about buying, but that depends on price etc. and it's your call.

Oh, and cold compression is another thing too; about a year ago I checked out a pair of 150 HP evinrudes, one was "blown" and the other was supposed to be in good running shape. After cranking it over and taking a cold reading on the "good" engine, I said "no thanks"; the compression was 70 on the lowest and 95 on the highest. A friend of mine bought the pair for parts, and the engine I thought was junk fired up the first time he turned it over. After running it for 5 minutes the compression was checked and found to be a solid 100+ per cylinder.

Jon "
 
" I just acquireed a 50 HP Joh

" I just acquireed a 50 HP Johnson. It has not been started in quite sometime, and is claimed to be good. For starters it needs a starter and I would like to give it a compression test. What should I liik for in compression. It has two cylinders, and I can turn the flywheel by hand?? is this normal?? It will be replacing my old 1962 75HP Jonson, now that was a good engine. Any help would be appreciated Thanks Jerry "
 
"Jerry..... Back up to the pre

"Jerry..... Back up to the previous page, go all the way to the bottom. YOu'll be able to click on that large button there to enter your message/question under your own heading. When you do, list the model number of your engine or, if you're sure of the year and hp, list the year, hp, make. Note that the model and serial number will be on a plate on the left (port) tramson bracket, and also on a core plug on the powerhead. It's normal to be able to turn the flywheel. The compression on those models are normally around 100+ psi. A engine sitting for any length of time will require that the carburetors be cleaned and rebuilt. Without the model number, it would be quite difficult to say what starter would be required. Get back to us and we'll see what we can do.

Joe
"
 
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