88hp OMC too cool on one head, OK on other...

[ledgefinder]

Here's a puzzler (at least to me). I just got a 1988 Johnson 88 SPL. On a test run, the starboard cylinder head is too cold (almost no heat at all after 5 minutes slow, just a bit of heat after 2 minutes full throttle). The port head is just about right - after 5 seconds, you've gotta pull your hand off it. I did pull the starboard head to do a thread insert, but am sure I got the gasket on there with slots in the lower starboard corner, as directed in my manual & on the gasket, and by common sense (looking at the flow layout of the head & cylinder). Any ideas what's going on here? Seems like thermostat is working, or else the port head wouldn't be correct temperature.

 

[DJ]

Re: 88hp OMC too cool on one head, OK on other...

ledgefinder,<br /><br />I just went through the same excersize with a 90 (same engine).<br /><br />Your v-4 has two thermostats, one for each bank. I replaced both-problem solved.

 

[ledgefinder]

Re: 88hp OMC too cool on one head, OK on other...

Ahh-haaaaa...the old two-thermostat trick. Thanks!

 

[Beernutz]

Re: 88hp OMC too cool on one head, OK on other...

Yeah, and if that trick bothers you, wait til you see the gynmastics you gotta go thru to replace them.