Water Temp Flucuation - brand new impeller kit installed

[TroyHogsett]

Was wondering if anyone could help me troubleshoot my 87 4.3l Cobra - I just installed an impeller kit last weekend - I bought an aftermarket - which I was not happy with - Chinese junk - the impeller housing fitment was not very good - it would bolt up but the center to center of the housing was longer than the bolt holes which you could visibly see as the bolt was way to the inside of the hole in the impeller housing. The install was uneventful - although I did see a piece of the old gasket fall into the housing when i was removing the old impeller housing. Not sure how noteworthy that is.

Lake tested the boat this weekend - and underway it is cooling fine - but when I go to idle in neutral the temp rises to (what I take is a cautionary zone) the top of the gauge swing. It cools right back down within 10 seconds when under way. I will include a pic of each place the gauge is sitting - one at idle - one under way. I don't remember the swing in previous years, but I am getting old. ha.

I am pretty sure I was told to spin the housing on clockwise - I was thinking maybe the fins were bent the wrong way?

Any help would be appreciated. Thanks

 

[Lou C]

I have used only OE OMC housings, impellers etc in 18 years of owning a Cobra and never got a bad one. That said Sierra might be an OK replacement. The fins will self correct. After I install a Cobra impeller I always run it on the water hose with the cover for the tail end of the upper gear housing off to make sure there are no water leaks around the impeller housing. Sometimes that litle O ring gasket can shift out of place when you install it. Also make sure that the bleed hole (little nipple on the impeller housing) is open, water should shoot out of that if you take off the little hose attached t it. This helps the impeller prime when you first put the boat in the water by letting air out of the housing.

If you don't have a local dealer (any Evinrude dealer can order OMC parts) you can get them from a variety of retailers, try to go OEM....

 

[TroyHogsett]

Thanks. I will re-order and replace. Is is a good rule of thumb to replace the housing itself - or do most just do the wear plate - stainless cup and impeller? Thanks

 

[Lou C]

as long as the housing did not distort from heat you can reuse it.

 

[TroyHogsett]

I got an OEM water pump kit yesterday - just to refresh my memory - the wear plate is non-directional correct? Also can I use grease on the o-ring or does a guy need the Johnson gasket sealer? Do you guys use gasket maker on the paper gasket - like the red/black that we all have in the tool box? Thanks!!

 

[Lou C]

I use OMC gasket sealer on the paper gasket the wear plate is non directional. The shop manual says to use the gasket sealer on the o ring for the housing but I found that it can slip out of place and found that the thick OMC triple guard grease holds it in place better...

 

[kpg7121]

Make sure you clean off all of the old gasket residue & sealer from the impeller housing. If you don't have a tight seal the system will suck air & cause an overheat. I use to carry an extra impeller in the glovebox & the tools to change it just in case. Been down that road before......

 

[Lou C]

After I install a Cobra impeller I always run it on the water hose with the cover for the tail end of the upper gear housing off to make sure there are no water leaks around the impeller housing. Sometimes that litle O ring gasket can shift out of place when you install it. Also make sure that the bleed hole (little nipple on the impeller housing) is open, water should shoot out of that if you take off the little hose attached to it. This helps the impeller prime when you first put the boat in the water by letting air out of the housing. ​