4.3 OMC temp question

[linuxusr]

Greetings all
I'm a little worried, and I am looking for guidance here. My 1997 4.3 runs at a temp of 200 when idling. Once I open up the throttle it will shoot down to 170. I replaced my impeller last season and the old one was in nice shape. So I don't think thats a issue. I am about ready to replace my thermostat.

I checked my maintenance guide and can't find recommend running temps. Is 200 normal idling temp or should I continue replacing the usual suspects.

Thanks for your assistance
Clayton

 

[bruceb58]

Re: 4.3 OMC temp question

That's way too high. Was it doing this after you replaced the impeller last year? This boat used in salt water? What is the condition of your manifolds? You have the batwing manifolds or do you have manifolds/risers?

If the manifolds are ok, sounds like you need to check the impeller again.

 

[linuxusr]

Re: 4.3 OMC temp question

Thanks for the quick response!!
Ya it was running this hot last year after I replaced the impeller. The boat has never been in salt water while I've owned it last 5 years. I have riser manifolds one is newer I had one crack a few winters ago. The other is in good shape. I was thinking of replacing my belts I noticed they are a tad loose. I wonder if they aren't able to spin the impeller fast enough.

What temp range should I be running at?

 

[bruceb58]

Re: 4.3 OMC temp question

Should be running 160 max.

And I just realized you have the SX drive since it is a 1997.

Do you have an IR temp gauge? If your impeller was not flowing enough, your manifolds would be getting very hot as well. They should also be less than 170 as well.

Does it do this on muffs as well or only in the water?

 

[linuxusr]

Re: 4.3 OMC temp question

I don't know if it does it with muffs I will check try it out tomorrow. Sorry if this is a silly question I don't have a IR temp guage. Could I measure the temp of the water coming out of the engine. Shouldn't that water be the same temp as on the temp guage on my dashboard?

 

[bruceb58]

Re: 4.3 OMC temp question

The temp gauge measures the water temp in the engine block. Once water leaves the engine block it mixes with more raw water from the impeller and makes its way to the manifolds and risers and then out. Temp will be completely different.

You can pick up an IR thermometer for $30 at Harbor Freight when its on sale.

http://www.harborfreight.com/catalogsearch/result?q=thermometer

If it works ok on muffs, you may have an air leak which is causing the pump to lose prime. One culprit is the oblong o-ring that is between the drive and the pivot housing.

Do you take your drive off regularly(annually)?