motor inspection

[HTHM]

I am going to look at a older Johnson ~ 43 yrs old, it has been winterized and stored for a year. Besides the bottom end fluid level, what else can I check? Will I be able to do a compression test without ruining the winterization?

[bigfish1965]

A compression test doesn't fire the cylinder but will vacate the fogging. Just refog the cylinders when done. I have no clue what numbers you should be looking for but just look for all numbers to be similar.

[POLLIWOGG]

If its been fogged you won't get a true reading anyway, so it should have good compression with the fogging oil in it or there is a problem.

[irishfield]

Yep she'll be full compression thanks to the fogging....unless there's a hole in the piston. Compression tests can be misleading and while a cylinder may hold 79/80 psi it does so because so much oil is making it past the rings it seals them for the compression test.

 

And for those that don't understand the 79/80 vs the general compression test gauge where you stick it in the plug hole and crank the engine... I do them by holding a piston at TDC and pressurize with 80 PSI. Generally a good cylinder will hold at least 70 of it. 75/80 is beautiful. 68/80 is when you start looking for problems.

Edited November 13, 2007 by irishfield

[aplumma]

I would caution you against buying a motor of that vintage without being able to repair it yourself. It will be cranky at best and if you need to send it to the shop something as simple as a coil will cost more than the motor is worth.

 

 

Art

[HTHM]

Thanks for your input everyone. The motor in question is attached to a lovely hull and I am only interested in getting a season or half a season out of the motor. The whole package is worth more than what is being asked for, esp in the spring.

Yes I should be able to service it myself and have it limp along for now.

[TennesseeGuy]

When you wrote you'd be looking at an older Johnson, I thought you were taking a job as a urologist in Tampa, Florida.

[HTHM]

When you wrote you'd be looking at an older Johnson, I thought you were taking a job as a urologist in Tampa, Florida.

With business the way it is right now, that might not be a bad idea.

[pikehunter]

Best of luck Hometown, you have received some good advise. Let us know how you made out with it.