1989 88 spl Evinrude

[ljf]

I recently replaced the diverters in the left head of this engine because this side was overheating. Now the left head runs cooler at slow speed but at 3500 it runs hot(180). The right side runs cool. The relief valves are new.
Any ideas?

 

[tashasdaddy]

Re: 1989 88 spl Evinrude

doesn't it have 2 tstats. one could be bad.

 

[ljf]

Re: 1989 88 spl Evinrude

But if the thermistat was bad,would'nt the left head run hot when going slow?
A temperature gauge shows 135.

 

[reload]

Re: 1989 88 spl Evinrude

Are you calling the thermostats relief valves?

 

[ljf]

Re: 1989 88 spl Evinrude

It is my understanding that the housing contains the thermistat,which controls low speed temperature,and the relief valves,,which open under high speed. My low speed temp is ok. Its the high speed that is running hot.
Changing the diverters helped the low speed temp,but the high speed is
still running hot-around 180. The right head is running cool.

 

[HighTrim]

Re: 1989 88 spl Evinrude

You are correct. The pressure and temp controlled cooling system contains the pressure valves, springs, and the t stats. The circulation of water through the cooling system by the water pump is controlled by the balanced action between the pressure control valves, water pump pressure and the t stats. When the power head and cooling system temps reach approx 145 deg F ( I believe on your motor) the t stats open, allowing heated water to pass through the water discharge. As engine speed is increased, water pump pressure opens the relief valves. This by passes the t stats, allowing the engine to run cooler at higher speeds. Always re torque your head bolts after an over heat. Make sure water is reaching the t stats properly via the water tube and that your intake isnt blocked. By diverters do you mean the water deflectors in the head??

 

[ljf]

Re: 1989 88 spl Evinrude

Yes,I thought they were called diverters but deflectors is correct. They were 2 tubular devices made of rubber. I replaced both. By doing so my slow speed temp improved but high speed improved only a bit.
Do you think there maybe salt clogged passages in that block?

 

[reeldutch]

Re: 1989 88 spl Evinrude

if your low speed temp is good but it overheats at high speed, probbebly you do not have enough pressure .
check the impeller for weak or cracked blades.
it could be the waterpump not making enough pressure (volume) to cool the block at high speed.

 

[ljf]

Re: 1989 88 spl Evinrude

Could the problem be in the waterpump even though the right head runs very cool to the touch?

 

[TD_Maker]

Re: 1989 88 spl Evinrude

I used to have the same Motor. It is my understanding that you must have taken off the heads and serviced the block. Are you absolutely sure you placed the rubber water diverters in the correct position in the water jackets? Also, did you clean out the passages with a soft wire brush before you re-assembled? It sounds like the motor was used in salt water, and perhaps it was neglected and not flushed out; Consequently, salt may have built up and clogged the water passages.

Also, if salt build up was a problem, make sure you replace the thermostats too. It is not a fun job for sure, but rusted or stuck therms will sure ruin your day (and perhaps Motor!)

By the way. The 88 SPL is a great old work horse motor. It does not ask for much, just a little attention every now and then, and she will run forever!

 

[reeldutch]

Re: 1989 88 spl Evinrude

yes your water pump could not make sufficient presure to open up 2 pressure relieve valves .it just might barely open up one.

 

[ljf]

Re: 1989 88 spl Evinrude

I only cleaned areas I could see after I removed the head(around the cylinders and passages in the head itself). All of the old diflectors were
removed,what was left of them. If there are any hidden passageways,I never got to them. If I was used for 18 years in salt water,I would probably be
clogged up too. Which brings me to a product I heard about called saltaway.
Does anyone have experience with this product?

 

[ezeke]

Re: 1989 88 spl Evinrude

edit

 

[ljf]

Re: 1989 88 spl Evinrude

Thanks for your input everybody. The water pump,even though changed last year,could be the problem.