New to forum - How to choose a leak down tester

[lakeviewman]

I just joined the forum and thought I'd introduce myself.

I live in NH and have have a 1985 Johnson 140 VRO outboard. I loaned it to a friend for a month and unforturnately when the low oil warning started going off, they ignored it. I got pretty conflicting reports after that, but the upshot seems to be that the engine isn't running well anymore.

I'm going to try and determine what's going on and hopefully repair it myself. I'm new to outboard repair but have done other mechanical work and am looking forward to the challenge.

After reading the forum a bit, it seems clear to me that I want to do both a compression and a leak down test. I have the compression tester, but need some help picking out the leak down tester. The prices seem to range from $400+ to $20 or so on E-Bay.

Can anyone recommend a low priced model/brand? Also, is there a difference between those intended for 4-stroke and 2-stroke engines? Any other features I should look for?

Thanks,

lakeviewman

 

[ezeke]

Re: New to forum - How to choose a leak down tester

Because of the positioning and size of the ports on your 140, the leak down test is difficult at best because of the need to keep the piston and piston rings balanced above both scavenger and exhaust ports. I personally believe that the compression test will be an adequate guide.

 

[wilde1j]

Re: New to forum - How to choose a leak down tester

Ditto above.

 

[tashasdaddy]

Re: New to forum - How to choose a leak down tester

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=94190

 

[samo_ott]

Re: New to forum - How to choose a leak down tester

I thought you could only do a leak down test on a 4 stroke? Does it actually work on a 2 stroke?

 

[ezeke]

Re: New to forum - How to choose a leak down tester

Not for me, samo_ott. Maybe others have had a different experience.

 

[iwombat]

Re: New to forum - How to choose a leak down tester

You generally use it to determine wear patterns in the cylinder. You take three measurements - TDC, middle, and BDC. Then you compare the readings and see if the cylinder has worn out of shape.

With a two-stoke all you can measure is the top of the cylinder. A compression test does a pretty reasonable job of that.

 

[lakeviewman]

Re: New to forum - How to choose a leak down tester

Thanks everyone, compression test it is.