Confused??? I found my old hand held compression tester and ran a check with that. Only gets to about 75psi! Compression is very low but why?

It starts well, idles well(once warm), and runs fine through the lower gears. No smoke at all, no fouling on the plug, etc. Could the valves be so out of adjustment to give these kind of readings?

Not likely, without problems starting too.

While you're at it, change your oil as more than usual contamination might be occurring. I recommend Mobil One 10W-40 or 0W-40, automotive types.

Alexd

Alexd

Nevermind. I doubted the accuracy of the old compression tester so I devised a test. I used the known pressure from my air compressor and checked it against the gauge. WAY off. I'm going to toss this tester and build an adapter for my good tester. I'll report back again tomorrow.

There are compression tests, and leak-down tests. I believe compression tests are preferential to warmed up engines (and oil).

Alexd

This is right in the middle of the 3 aluminum openings and facing down to the ground right? Is it part #34-35 on this chart and if so how would you get a drill bit in there without removing the carb? Any vids showing how to do this without removing the carb? Thank

OEM Carb Parts

Here's a vid I found, ( but with the carb removed )

Cap Removal

Kenny4

Yes, its the brass plug in the boss that faces down. There may be a very small hole in it already. You can loosen the clamps and rotate the carb in place without removing the throttle cables. Rotate it about 45 deg and you can get at the plug to remove it.