1997 150 Ocean Runner Running Hot

[phinsup]

I've got one last issue to diagnose, the lower end was rebuilt about 8 months ago and the impeller was replaced.<br /><br />i believe I have narrowed this down to the thermostats, I pulled them today after running hot and am going to test it tomorrow without them, if it runs cool, then I will replace them and hope that does it.<br /><br />The tell tale pees hard at high and low rpm, it seems to run hottest at low rpm. I haven't actually overheated the engine, it just runs hot, near the top of the gauge all the time and prior to pulling the thermostats the cylinder heads especially the right one would feel hot. Hopefully that will do it and I can throw new stats in this week and be rolling again.<br /><br />Anything else to look for? Are these tstats a common issue?<br /><br />Thanks

 

[Solittle]

Re: 1997 150 Ocean Runner Running Hot

These engines are supposed to run hot - you should be able to put your fingers on the top of the head for not more than a few seconds. Is the overheat alarm going off? You may want to check with a heat gun or temperature sticks.

 

[phinsup]

Re: 1997 150 Ocean Runner Running Hot

Nope no overheat alarm, The alarm does work and I put a temp guage in that actually has numbers on it. It runs around 160 or so most of the time.<br /><br />I think I'll snag the heat sticks next week and give that a try.<br /><br />thanks

 

[clanton]

Re: 1997 150 Ocean Runner Running Hot

It should run about 160 at low rpms.

 

[phinsup]

Re: 1997 150 Ocean Runner Running Hot

OK I pulled the thermostats and it didn't go above 120 the whole day, idled rough of course because it was so cool.<br /><br />So this would lead me to assume that the thermostat(s) were plugged. Could it be anything else? Is it possible the impeller isn't able to make enough pressure to open the tstats? Should I just go ahead and replace the tstats and the impeller?<br /><br />Thanks again!

 

[clanton]

Re: 1997 150 Ocean Runner Running Hot

120 is to cold. 140F at 900 rpms, 160F at 5000 rpms, checked with a digital pyrometer or melt stick.

 

[phinsup]

Re: 1997 150 Ocean Runner Running Hot

Is it reasonably easy to do the impeller/waterpump? I read the manual and a bit scared of bending the shaft, I am hoping it would take some work to bend that shaft, but just wanted to double check.<br /><br />I'll get t stats monday.

 

[phinsup]

Re: 1997 150 Ocean Runner Running Hot

Well that was easy, yanked the lower end in about 20 minutes. I did notice that the top of the shift shaft had a bend in itm I assume that is factory?<br /><br />You'd have to work pretty hard to bend the driveshaft.<br /><br />Anyhow, here's the update. Impeller looks brand new, however the o-ring that goes around the impeller was pinched on the inside of the impeller for a good 3rd of the way around and obviously wasn't sealing. I am going to get new seals, housing and impeller monday, that should solve my headaches!