Evinrude 1998 90hp Overheating

[Lindanel]

Got the boat running a few weeks ago, started up like it ran yesterday, even through the cold winter. Keep in mind I changed the thermostats last year.

The overheating alarm went off after a few minutes. Checked the wiring and determined it was running hot and the alarm was not due to a bad ground.

Bought a water pump kit, and replaced it this weekend, and she is still running hot.

There doesnt seem to be any water running throught he rubber hoses that go from the thermostat housing to the cylinders. Could those thermos need to be replaced again? I am not sure what direction the water flows so I am not sure if those hose should be full of water even before the thermos open, but they were dry as a bone when I pulled one off. I am hoping the water is sitting behind the thermostats and just not getting through.

Any suggestions.

Thanks as always, this forum is a life saver.

 

[Chris1956]

Re: Evinrude 1998 90hp Overheating

on a '98 Johnny 90HP Motor, the thermostats are under covers on the cylinder heads. There is no rubber hoses running to a "thermostat" housing.

As a general question. could pieces of the impeller be blocking the waterpassages? Does your hose supply enough water to cool that motor?

 

[Lindanel]

Re: Evinrude 1998 90hp Overheating

Chris,

There are two 2" rubber hoses that run from the Thermostat housing into the side of the cylinders. The Thermostat housing is located on the bottom when your standing behind the engine, with the spark plugs looking at you. Kind of tucked behind the lower enginer cowl. It was hard to get at.

The motor is the Evinrude 90 SPL E90TSLECM.

Last year I bought the kit, I replaced both thermos, a rubber spacer, a few gaskets, and the two hoses.

I appear to have a good pee stream until she stars warming up she gets inconsistent and spitty. I made sure I had a strong source of water on the ear muffs. When I did the impeller, I was sure to clean the screens and there didnt appear to be anything to impead the water in the lower half anyway.

 

[bob johnson]

Re: Evinrude 1998 90hp Overheating

your description and the "M" code means you have the crossflow motor...

bob

 

[ondarvr]

Re: Evinrude 1998 90hp Overheating

Did it work correctly right after you changed them last year?

 

[Lindanel]

Re: Evinrude 1998 90hp Overheating

It did run good after replacing them, I actually found my overheating last year was actually an electrical problem, but no harm done in changing the thermostats.

I did notice late in the season last year that I was running warmer that usual. It wasnt overheating but running warmer then it has all season.

 

[ondarvr]

Re: Evinrude 1998 90hp Overheating

You said the pee stream starts to spit and sputter, one cause of this is a head gasket leak, the combustion pressure leaks into the water jacket and over powers the water pump stopping the flow. Head gaskets can go bad from over heating, or just on their own.

 

[Lindanel]

Re: Evinrude 1998 90hp Overheating

That would make sense as a mechanic I had look at it last year said the gaskets looked like they would need replacing in a year or so.

Is this a tough job? I am quite handy, just do not want to bit off more than I can chew?

 

[ondarvr]

Re: Evinrude 1998 90hp Overheating

If you can do a compression check first, you may be able rule out a head gasket if that's not the problem.

Head gaskets are easy to change though, only takes few minutes to get it off, cleaning the gasket surface will take more time than anything else.

 

[bob johnson]

Re: Evinrude 1998 90hp Overheating

if it were me, id take the lower cowling off and run the motor til the t-stats opened..

then shut her down and start undoing the head bolts..

its all fun and games till you snap a head bolt. or two, or three and the "nothing" job that should take 1/2 hour......... last 4 months!!!!!!!! if it doesnt cost you $750!!( take it to a mechanic)

warming the block up will help prevent this a little.

good luck

bob

 

[Lindanel]

Re: Evinrude 1998 90hp Overheating

I am going to give it my best shot, as the mechanics around these parts are all theives and unreliable. Besides, after this, I should be able to tear this baby down and rebuild her in my sleep.

I really appreciate all the input gentlemen. I will test the compression first and take it from there.

 

[WT2]

Re: Evinrude 1998 90hp Overheating

The crazy thing about this is that the same thing happened to me! After I took apart my lower section of the motor I put it together and it all seemed to fit fine but the tube that came up from the pump moved about 3/4 inch which means it was not in the rubber seat and not pumping. I toasted my thermometer before I figured it out. So if you were in the lower section the pickup tube would be the first thing I would check out! Good luck

 

[Lindanel]

Re: Evinrude 1998 90hp Overheating

I will definetely check that tube first and make sure its mated up to the impeller housing. Thanks!

 

[Lindanel]

Re: Evinrude 1998 90hp Overheating

Well, I broke one bolt in the head, as you warned me. It was the only one that gave me a problem. I ordered a good bit, to drill through the stainless steel and wonder if there is anyway to removed the engine cowl, as I can not fit the drill in there, or do I need to pull the powerhead out of there?

What a mess, amazing one bolt could be so tragic.

 

[bob johnson]

Re: Evinrude 1998 90hp Overheating

of course there is a way to remove the lower cowling...you probably only have 4 bolts holding it together...but youll have to take the cables off.

you could probably get away with just laying the port side over and letting it hang with all the wiring and gas line...9if your is anything like mine...(which it might not be!!)

dont try to drill on an angled broken bolt...try and get that thing flat and punch it with a prick punch in the center before you start to drill...

start with a smaller drill than needed to see that you stay on center...then go with the tap drill size...

take your time drilling...the aluminum will drill WAY WAY easier than the broken bolt, so once you start to wonder, you can get in trouble FAST!!

good luck

bob

 

[Lindanel]

Re: Evinrude 1998 90hp Overheating

Thanks Bob, busy for the next week, hope to get to it next week and I will let you know how it works out.