Re: 70hp idling characteristics?

[DAN ANDERSON]

I just thought of another part of the update kit. A water pump kit #432955 with 6 blade impeller and related parts. You get different vernitherm springs and instruction. Two elbows for the exhaust cover.
The tap to move the elbow location is 1/8" NPT. Pipe tap. Standard depth to tap is 2/3 of tap length. You should not have a problem hitting anything. 11/32" drill hole size.
If you take the vernitherm out and then drop it back in the cover you can tell if it seats. If it wobbles around then needs to be filed just a bit. You can pull the pin and file the square end down until it seats in the cover. The engine should warm up to 125. That’s about as good as you will see.
It is hard to tell cylinder condition on loopers (2 & 3 cylinders) in particular with compression checks. Just a few pds. can indicate scoring. I would pull the head before going too far with your trouble-shooting. Could save a bunch of headaches. When you see the idle screw turned all the way in on a 2 or 3 cylinder looper, beware? Most of the time the head gasket can be saved, gasket sealed, and put bad on if things are OK. Just my experience!

Dan in TN