Location of thermostat on 84 merc 115

[sparky4612]

I'm trying to determine why my 1984 115hp inline 6 does not pee. It did when I bought it last fall but now it doesn't. I rebuilt the water pump today just in case the impeller went bad but it all looked good. Does this motor have a thermostat? If so where is it?. When I started it with muffs last week it was cold so I'm wondering if the thermostat didn't have time to open ( I only ran it for a minute or less). Any help is appreciated! Thanks Greg

 

[Chris1956]

Re: Location of thermostat on 84 merc 115

I do not think your motor has a thermostat. Check the telltale for clogging. Pull the telltale hose off the elbow on the cylinder head water jacket cover and see if the water flows freely. If not you have a clog in the water tube or some other issue. You might need to drop the gearcase to diagnose.

 

[Texasmark]

Re: Location of thermostat on 84 merc 115

Agree. Had the last of the 115 towers and it had none also. Apparently either Merc couldn't find a place for it in that 40 year old basic engine block design, or they felt that their 40kv electronic ignition would make up for the lack of it which it did nicely.

Something to be said about reliability without one. Never a stuck shut stat to be had with the towers and I have had 2 engines (one OMC and my current '02 Merc) with stats that failed by sticking shut; both were bought used and the stuck stats came with the engines.........at no extra charge, Ha Ha! Thanks, but no thanks. The guy that sold me the OMC said that it was a HOT engine. It was HOT alright! One day if finally caused the engine to seize at WOT resulting in a .030 over bore job. After that, I realized why it ran great when I first turned it on but after about 15 minutes it started to run rough.....oh yeah, that was because it was a HOT engine......and the guy was my best friend at the time......at the time.

Mark