'79 Johnson 35hp tiller purchase.... things to check before

I'm looking at picking up a '79 Johnson 35hp. I'm mechanically inclined, but most of my experience is with cars and trucks. What should I check prior to laying cash on the table for the motor?

Obvious things to check:

-Starts easily and runs
- Compression (hopefully he'll let me hook up a compression gauge)
- Check LU oil for water contamination

Any other tips? It'd be greatly appreciated.




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not so related to the motor, but, look around his place
like the garage, outside, etc to see how he takes care
of his stuff.

look for discolored paint on the block. evidence of a past overheat issue.
fresh paint on the block - attempt to cover up a past overheat issue.
any wires that appear to be melted or taped up should be double checked.
yeah, I learned these tricks all by myself on the same motor.

good luck !!!

Johnny said:

not so related to the motor, but, look around his place
like the garage, outside, etc to see how he takes care
of his stuff.

look for discolored paint on the block. evidence of a past overheat issue.
fresh paint on the block - attempt to cover up a past overheat issue.
any wires that appear to be melted or taped up should get your attention.
yeah, I learned these tricks all by myself on the same motor you have.

good luck !!!

Click to expand...

Great tips! Thanks!


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If he doesn't let you check the compression walk away for sure.

What's normal compression on these motors... 140?


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from what I have read, 90-140 is the acceptable range.
120 for an older used motor would be good.
mine was 90 top and bottom and it ran great.
should be no more than 10% difference between the cylinders.
do not spray lube into the cylinder prior to testing,
it may give you less than accurate numbers.

Clutch dogs. Make sure it doesn't pop out of gear these motors are notorious for it.

Actually, in 1978 there was an update that helped out the jumping out of gear issue and another in 1982 or 84. The later engines had great gearcase life.
However, that being said this may be one of the engines that had the funky water tube set up with the grommets and plastic tube up in the midsection.
Definitely look for signs of overheat.

I ended up passing on the motor. It was in very rough condition. The search continues...


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Pappy said:

Actually, in 1978 there was an update that helped out the jumping out of gear issue and another in 1982 or 84. The later engines had great gearcase life.
However, that being said this may be one of the engines that had the funky water tube set up with the grommets and plastic tube up in the midsection.
Definitely look for signs of overheat.

Click to expand...

Thanks. I have a couple of the older ones. What a pain in the butt!

shooter5635 said:

I ended up passing on the motor. It was in very rough condition. The search continues...


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Click to expand...

Trust me, you did the right thing!