jamoore
08-17-2001, 09:16 AM
With the help of the folks here, I have been chasing a few problems with my 1987 175hp Mariner. It seemed to be running hotter this year so I just finished replacing the impellor, poppit valve and removed the thermostats (replaced with s/s washers w/ the 1/8" holes)and also put in a new temp sending unit. Had it running on the hose the other night and seemd to be cooler on the gauge. Since I was never real confident in the gauge, I also bought a infra-red thermometer. While it was running, I played around checking the head temps. What I found puzzled me. The right cylinder head is reading 15 to 20 degrees hotter than the left side. This doesn't seem normal to me and I was hoping for some more knowledgeable input on this. Is this normal or should I be looking for additional problems with the right head? I ran out of daylight before I could do a real in-depth comparison but the left side was generally reading around the 140 degree range while the right side was in the upper 150 range. All three cylinders on each side were within a few degrees of each other but a definite difference between left and right. I have checked the compression and all cylinders are within a few pounds of each other. I was going to try a washer with a larger hole on the right head to see if anything changed but didn't have time. As always, your comments are greatly appreciated!! Joey