Logo
FULL SITE MENU

1979 johnson 200hp

Compression testers are in the order of $40 and that would be cheaper than dealer minimum charge.--Easy to do yourself.
 
In agreement with "racerone" that it is a easy test to do... no need to take it to a dealer.

Compression testers can be found even cheaper yet at Wal*Mart, K-Mart, various auto part stores, etc. Spark testers are also available at various auto part stores. However a home made spark tester can easily be build as explained below.

I prefer the compression tester that has a rubber tip where one simply holds the tip snugly in the spark plug hole.

On your model engine, have "all" spark plugs removed for either test so as to have the highest cranking rpm available.

On the compression test, allow the engine to crank over three revolutions... more is okay but at least three. On the spark test, the gap setting for the spark to jump must be 7/16"... and the spark should be a strong blue lightning like flame... a real SNAP!

(Spark Tester - Home Made)
(J. Reeves)

You can use a medium size philips screwdriver (#2 I believe) inserted into the spark plug boot spring connector, then hold the screwdriver shank approximately 7/16" away from the block to check the spark or build the following:

A spark tester can be made with a piece of 1x4 or 1x6, drive a few finishing nails through it, then bend the pointed ends at a right angle. You can then adjust the gap by simply twisting the nail(s). Solder a spark plug wire to one which you can connect to the spark plug boots, and a ground wire of some kind to the other to connect to the powerhead somewhere. Use small alligator clips on the other end of the wires to connect to ground and to the spark plug connector that exists inside of the rubber plug boot.

Using the above, one could easily build a spark tester whereas they could connect 2, 4, 6, or 8 cylinders all at one time. The ground nail being straight up, the others being bent, aimed at the ground nail. A typical 4 cylinder tester follows:

..........X1..........X2

.................X..(grd)

..........X3..........X4

Thousands of parts in my remaining stock. Not able to list them all. Let me know what you need and I'll look it up for you. Visit my eBay auction at:

http://shop.ebay.com/Joe_OMC32/m.html?_dmd=1&_ipg=50&_sop=12&_rdc=1
 
joereeves said:
In agreement with "racerone" that it is a easy test to do... no need to take it to a dealer.

Compression testers can be found even cheaper yet at Wal*Mart, K-Mart, various auto part stores, etc. Spark testers are also available at various auto part stores. However a home made spark tester can easily be build as explained below.

I prefer the compression tester that has a rubber tip where one simply holds the tip snugly in the spark plug hole.

On your model engine, have "all" spark plugs removed for either test so as to have the highest cranking rpm available.

On the compression test, allow the engine to crank over three revolutions... more is okay but at least three. On the spark test, the gap setting for the spark to jump must be 7/16"... and the spark should be a strong blue lightning like flame... a real SNAP!

(Spark Tester - Home Made)
(J. Reeves)

You can use a medium size philips screwdriver (#2 I believe) inserted into the spark plug boot spring connector, then hold the screwdriver shank approximately 7/16" away from the block to check the spark or build the following:

A spark tester can be made with a piece of 1x4 or 1x6, drive a few finishing nails through it, then bend the pointed ends at a right angle. You can then adjust the gap by simply twisting the nail(s). Solder a spark plug wire to one which you can connect to the spark plug boots, and a ground wire of some kind to the other to connect to the powerhead somewhere. Use small alligator clips on the other end of the wires to connect to ground and to the spark plug connector that exists inside of the rubber plug boot.

Using the above, one could easily build a spark tester whereas they could connect 2, 4, 6, or 8 cylinders all at one time. The ground nail being straight up, the others being bent, aimed at the ground nail. A typical 4 cylinder tester follows:

..........X1..........X2

.................X..(grd)

..........X3..........X4

Thousands of parts in my remaining stock. Not able to list them all. Let me know what you need and I'll look it up for you. Visit my eBay auction at:

http://shop.ebay.com/Joe_OMC32/m.html?_dmd=1&_ipg=50&_sop=12&_rdc=1
Click to expand...

Thank you much for the information .
 
Back
Top