Sounds more like you're running on 3 cylinders, then have the 4th cylinder cut in suddenly. If its a sudden, instant grab of power... that's ignition.

Trouble shoot it... compression, plugs removed for a spark test.

Yes.
I have already tested compression on all cylinders and they read approximately 110lbs on each.
I also recently replaced all spark plugs but have not tested spark from each cylinder.
I will test for spark but if its an intermittent issue will I get a true read?
Thanks for your help.

What type spark plug are you using and what is the gap?

It is necessary to have all spark plugs removed and have a spark tester where the spark gap is adjustable... the gap must be set to 7/16" for that type ignition. The spark should jump that 7/16" gap with 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:

joe_omc32 | eBay