1987 Johnson 88SPL how do i know if thermostats are opening?

[snookuda]

I am trying to make sure my 1987 88HP Johnson outboard engine is cooling properly. I replaced the waterpump already.

My question is if running on ear muffs should water be coming out of 2 exhaust housings on the lower unit once it is warm or will this only happen in the water.

I thought i remember that water would come out of these 2 lower unit exhaust ports when the engine got warm, but i recently ran the engine for 15 minutes on ear muffs and water did not come out of the exhaust ports. The engine is peeing fine. Is there way to tell if the thermostats are working properly, and what items should be replaced if they have not been replaced in several years? And is this a big job on this motor, Johnson 1987 88SPL?

The motor recently overheated and my dad and i replaced the water pump.

Thanks,
Steve

 

[Big Bubba]

Re: 1987 Johnson 88SPL how do i know if thermostats are opening?

SNOOKUDA,

I have the same motor. With my motor, no, the water doesn't come out the 2 each exhaust relief holes at the back of the motor below the top cowling when it is running on the ear muffs but it does when it is submerged in the lake. Know for the cooling you have a overheat warning horn in the remote control by your drivers seat that will go off if it overheats, if it is working correctly. You can also, after it has warmed up to temperature for about 10 minutes, lay your fingers on each of the heads or the flats of the block and count to about 4 seconds until you have to remove your fingers and you should be good to go. To me if your warning horn is working correctly that will sound when it overheats and you know that your engine is overheating. The others on this board say to get those temperature crayons say form Autozone and lay them on the heads after it has reached temperature and see if they melt and if they do it is overheating. I believe after reading the others post that the enigine runs about 143-153 degrees for normal operating temperature, but don't quote me on it. The others will give you more advice. How do you like your 88 SPL? Mine has been great and I just rebuilt the 2 carbs and hope they work good in the lake. I have cranked the motor over after the carb rebuild on the ear muffs and she ran great but the water might be another story. Take care, Bob

 

[tashasdaddy]

Re: 1987 Johnson 88SPL how do i know if thermostats are opening?

the stats may not open on muffs, due to rpms, if you can hold your hand on the top of the head for a 3 count, it is ok. or you can get the thermal heat sensor, and take it's temp. stats open a 140, temp should range 140-160 the highest. i've owned several 88 and never changed the stat.

 

[Big Bubba]

Re: 1987 Johnson 88SPL how do i know if thermostats are opening?

I just got threw rereading your post again and noticed that you say it overheated in the last sentence. Mine did that after I rebuilt the carbs and I realized that I wasn't getting the full flow of water out of my garden hose and I realized that there was a slight kink in it slowing the water flow down so I fixed that and a few more in the hose and the water came out of the hose faster and more fuller and I ran the motor again for about 15 minutes and never got the horn again so hopefully that was all it was. Just nake sure your water supply on land is sufficient to keep the power head cool. Basically my water hose was hard as a board becuase it was cold the previous night and it only got up to 52 degrees the day I cranked her over so the garden hose wasn't fully warmed up where it was relaxed. I should have waited until now to crank her over becuase the weather is warmer in the 60's and the garden hose is more relaxed and flexible where before it was very hard to work with becuase it was hard and not flexible. Have you changed out the thermostats, if not I would do those too. It is not a hard job at all just make sure you remove the lower cowl panel which is pretty small and take the 3, I believe 3/8 or 7/16 botls out and wolla the thermostas are out. The thermostat is located between the 2 heads at the back of the motor and there is 2 black rubber hoses connected to it comming from both heads from the right and the left side. I got my thermostat kit off of Ebay and did it myself. Just make sure you pay attention to how everything goes back togteher by printing off the thermostat picture of your motor off the Evinrude/Johnson parts break down site on-line and you should be golden. Take care, Bob

 

[snookuda]

Re: 1987 Johnson 88SPL how do i know if thermostats are opening?

Thanks for the quick reply's. The motor is used in saltwater in South Florida, very hot. My dad and i just replaced the water pump kit. As far as i know the thermastats have never been replaced (at least the last 10 years). If the heads stay cool, is there any reason to replace the thermostats? I herd that it may help the engine idle better, any truth to that? Also, running on the muffs, i cannot get the water to come through the exhaust ports just above the cavitation plate, i thought water was suppossed to come through here when the thermostats opened when the engine was warm?

 

[Silvertip]

Re: 1987 Johnson 88SPL how do i know if thermostats are opening?

If the stats aren't opening, the engine will overheat at idle. They can also stick open which can create an idle issue because the engine is running too cool. As was pointed out, the ports at the back of the engine are relief ports and you should see water only when the lower unit is in the water as that's when the backpressure creates the need for the relief ports.

 

[tashasdaddy]

Re: 1987 Johnson 88SPL how do i know if thermostats are opening?

10 years in south Fl salt water is reason enough to change them.

 

[emdsapmgr]

Re: 1987 Johnson 88SPL how do i know if thermostats are opening?

The engine telltale will operate normally and the engine can still overheat. The telltale is a good indicator of a strong pump, but does not indicate whether the thermostats are functioning properly. The engine has 143 stats in it and will run normally up to 155 or so. 212 degrees gets you the overheat horn-which shuts back off at 175. I agree with daddy, that it they are a candidate for replacement. The hand test method is good, if you have experience with it. A laser gun is a great (not too expensive) way to accurately determine the head/block temps. When you have the thermostat housing apart, make sure you check the valve body. It has two pinholes in it that frequently plug up. If either is plugged, that side of the block will overheat at idle, even with new thermostats.

 

[snookuda]

Re: 1987 Johnson 88SPL how do i know if thermostats are opening?

This is actually the ports i was wondering if water should come out of when running on the hose and the engine is warm. Not the upper exhaust holes. Here is a pic.

 

[tashasdaddy]

Re: 1987 Johnson 88SPL how do i know if thermostats are opening?

no unusal.

 

[Vic.S]

Re: 1987 Johnson 88SPL how do i know if thermostats are opening?

Is there something I dont know or could the thermostats simply be removed and tested by heating slowly in a pan of water to
a.) check that they start to open at the specified temperature (143F?).
b.) continue to open fully above that temperature and
c.) close again when they cool

opening up the housing would give the opportunity to check the "pin holes" mentioned as well

 

[darrklim2]

Re: 1987 Johnson 88SPL how do i know if thermostats are opening?

Is there something I dont know or could the thermostats simply be removed and tested by heating slowly in a pan of water to
a.) check that they start to open at the specified temperature (143F?).
b.) continue to open fully above that temperature and
c.) close again when they cool

opening up the housing would give the opportunity to check the "pin holes" mentioned as well

Probably would work to do that for testing them. Since the thermostats have already seen at least 10 years of use I would recommend to just replace them. For the relatively low cost of the thermostats it would definitely be worth it. Especially since it would already be apart. IMO

 

[pixelsnot]

Re: 1987 Johnson 88SPL how do i know if thermostats are opening?

Hi

I have the exact same motor. 87, 88SPL. I have an overheat alarm at HIGH RPM. After about 4 or so min at 70% throttle or better. It will idle ALL DAY at 0%-70% or so with out overheat alarms.

I have heard that it may be corrosion in the water jacket, the deflectors. BUT if I was to REMOVE the thermos all together wouldn't that open up a little more water flow. I live in Florida as well. Water temp on the river now is 80-85 degrees. I can live with a rough idle for a few minuets before the heads warm up.

Any ideas? Would removal of the T-Stats increase water flow at all?

Thanks a lot guys!!

Trent

 

[brett1970]

Re: 1987 Johnson 88SPL how do i know if thermostats are opening?

im also new to the forum and have an 88spl that i just bought. It's a 94 model. When i run it on the muffs very little water comes out of the nipple indicator on the engine lower cowl on the starboard side. Is this normal?Water seems to be coming out everywhere else it should and the cylinder heads are not hot to the touch. Is it that it cant get to the correct operating temp at idle or is it the thermostats are not working. I'm not an outboard mechanic by any means so any help would be appreciated. I've also only ran it about 3-5 minutes on the muffs if that helps.
Sorry about the long winded post.Any help would be appreciated.

Thanks in advance

 

[kenmyfam]

Re: 1987 Johnson 88SPL how do i know if thermostats are opening?

Check the stats in hot water with a meat thermometer.
Works for me !!!

 

[brett1970]

Re: 1987 Johnson 88SPL how do i know if thermostats are opening?

thanks. I will try that. Exactly where are they located and what do i have to do to get them out?
Thanks again.

 

[kenmyfam]

Re: 1987 Johnson 88SPL how do i know if thermostats are opening?

thanks. I will try that. Exactly where are they located and what do i have to do to get them out?
Thanks again.

Check this link out. Plug in your make, year and model number then find it on the available diagrams.

http://shop2.evinrude.com/Index.aspx?s1=4ab89e1262a8c38350c150b284f0b36b&catalog_id=5&siteid=1

 

[emdsapmgr]

Re: 1987 Johnson 88SPL how do i know if thermostats are opening?

The thermostat housing is behind the block at the top of the exhaust housing, in the lower cowling. A hose from each head feeds into that housing. There are both thermostats and pressure relief valves in that housing. Be sure to check the pressure relief valves to be sure they are not head deformed and also in need to replacement. Check the valve body-it has a small hole in the center, at the top-it needs to be open/clear.