water flow on 96 johnson 112 spl

[66 joe]

have a overheating problem with my 112 spl; both heads are getting up and above 200; (with infrared gun)
First thing i pulled was tstats (pain in da a); both looked ok, ordered replacement kit and will change regardless.
impellar was changed last year, but while t stats off, and motor on flush muffs, I have no water flow throught t stat housing. I started motor with water on muffs, ( all intent to turn it off when water flows out housing) but no water came out??!?!??!??!? turned it off before it got too hot.
impellar? clog somwhere? Im trying to find out why i was overheating. Will more than likely change impellar,, but want to find exact problem.

Thank you, joe

 

[kmarine]

Re: water flow on 96 johnson 112 spl

Impellers require regular maintenance and seldom last more than a few years. Always with impeller service for any coolin issues. Make sure to check for blockage of imperrer pieces and other foreign matter at this time.

 

[emdsapmgr]

Re: water flow on 96 johnson 112 spl

200 is too hot. 143-150 is normal. Usually OMC impellers on these engines last for years. It's unusual to have an impeller failure after one season, but it is possible if you have no water to the thermostat housing. You did not mention anything about the telltale: A good impeller should provide water to the telltale first. Make sure the lower cowling telltale nozzle is not plugged up. If you have a strong telltale, but no water to the thermostats, you may have good impeller but- likely a water restriction in the powerhead. If that's the case, you may want to pull the heads and the head covers off to visually inspect the water passages in the block/heads. (esp if this engine is used in saltwater.) Check for debris accumlation around the cyls. Make sure the water deflectors (rubber) are located (positioned) correctly to direct water flow around the cylinders.

 

[Fleetwin]

Re: water flow on 96 johnson 112 spl

I would drop the lower unit again. Perhaps the water tube (pump to block) did not get "stabbed" correctly when the lower unit was bolted back in place. Or, the o-ring may be missing.

 

[rothfm]

Re: water flow on 96 johnson 112 spl

Above posts are good advice. This is just an fyi, as I dont know if anyone was messing with head gaskets. They have ports/openings that HAVE to be oriented correctly otherwise will block water flow to parts of the heads. There are some threads on here about that. I had to very careful when Installing my new ones. Just food for thought.

 

[boatguya1]

Re: water flow on 96 johnson 112 spl

Also the above mentioned deflectors have a tendancy to swell over time blocking more than the flow they were supposed to.

 

[66 joe]

Re: water flow on 96 johnson 112 spl

Also the above mentioned deflectors have a tendancy to swell over time blocking more than the flow they were supposed to.

so it looks as if water goes through block before t-stat housing? (according to shop manual)
I did just replaced head gasket on port side, good deflectors and kinda seems impossible to re-install it incorrectly, considering water port on bottom and head gasket saying up on top part. power head just rebuilt with new water pump.
is there a way to back flush water flow, I dont want to re-install thermostats, till i make sure im getting water flow.
I did have a good tell tale also thanks joe

 

[66 joe]

Re: water flow on 96 johnson 112 spl

all this trouble started with over and not having over -heat alarm going off, bad alarm horn replaced now
, and motor went into slow mode. fortanetly, no damage, just head gasket, replaced and good compression in all cylinders