Warning horn on 1991 88 HP...

[Guvner]

Was getting ready to take my pontoon up to the lake when I test ran it again. This time it ran fine for 5 minutes, water shooting out of the **** hole very hard but as stated the warning buzzer went off. I'm an air conditioning guy so I quickly (well 5 or 10 minutes or so) went and got my digital surface temp indicater. I presume the one lead plugs coming from the outside of the engine are the sensors, if not please tell me where they are. I hit both sides with the temperature reader and it quickly have me 164 degrees on the left side (viewed fromt the rear) and 143 degrees on the other head at the same symmetrical spot. <br /><br />I'm assuming that I have more of a clogged passageway than a bad water pump. Anything I can do as not being mechanically challenged? Boat motor was completely rebuilt 3 years ago and sat in the water till December of this year. Drydocked since. Now that I think about it the buzzer came on when I pulled it out of the water on a cold day in January just as I pulled it onto the trailer. Shut it off, pulled it on the trailer and forgot about it till today. I did look last time and it was spitting water. <br /><br />Thanks for any suggestions as to how to flush system or whatever...<br /><br />Thanks... Gary

 

[DJ]

Re: Warning horn on 1991 88 HP...

You can just about bet that one of your thermosats is clogged or stuck. The termostats are located at the base of the block between the cylinder heads. The two hoses going out of the heads lead to the stat block.<br /><br />It s NOT an easy job to get at them on that engine, however it can be done with some patience. You have to loosen the lower pan to get about another inch of clearance. You also have to remove the band that goes around the top of the exhaust tower.<br /><br />Make sure you replace them, do not run it without them.

 

[Guvner]

Re: Warning horn on 1991 88 HP...

Looking again at my worthless Clymer manual I am returning here to ask if where the two 3/4" or so sized hoses dump into the block that is bolted with a left, right and center bolt along with what looks like a spacing plate to the bottom of the engine. If so then just take off the bolts that would probably allow you to drop the outside lower housing for better clearance. (As you spoke of..) I presume the thermostats are available froom a Johnson dealer.<br /><br />Thanks for the quick answer in any case... <br /><br />Gary

 

[Marc J.]

Re: Warning horn on 1991 88 HP...

Did mine a few weeks ago, thanks to the help of the friendly, knowledgeable folks on this board. It was suggested that drilling a tiny hole in each t-stat or each by-pass valve will prevent trapped air & water from creating a temporary overheating condition. New by-pass valves and grommets wouldn't hurt either, they're pretty cheap.

 

[Guvner]

Re: Warning horn on 1991 88 HP...

Where do the new by-pass valves and grommets go? My dealer going to have them? <br /><br />Going on search now to try and find about about your experiences... Thanks... Gary

 

[DJ]

Re: Warning horn on 1991 88 HP...

The dealer will have them. The whole mess is pretty cheap, just not easy to get to.<br /><br />I agree on drilling the hole.

 

[Guvner]

Re: Warning horn on 1991 88 HP...

I can't believe it... The Clymer manual had the entire thing broke down. I'm assuming I only have to take the back 3 bolts off I can change the thermostats and valves. (Check valves?)<br /><br />What about this hole to be drilled? Where do you drill it exactly and what size?<br /><br />Thanks guys... Really appreciate it... Gary

 

[Marc J.]

Re: Warning horn on 1991 88 HP...

I drilled a small hole through each by-pass valve, using the smallest bit I could scrounge up. Others have used a file to create two small notches 180 degrees apart on the outer diameter of each. Earlier t-stats designs and aftermarket ones have a small hole already. The new OMC ones do not. You could drill a hole in each t-stat, but a hole in each by-pass valve will do the same thing and will be easier. A standard box-end wrench and a lot of repositioning worked for me in getting the bolts out. It's really in a bad spot. When putting the whole thing back together, set the new parts in the t-stat housing and apply a little gasket adhesive to the mating surface. Press the gasket to the housing and let it set up for a little while. The gasket will hold it all together while you fight the springs. If any of the three bolts break, replacements must be stainless steel. Also apply some gasket adhesive to the threads. It's better suited for the marine environment than anti-seize. Good Luck.

 

[Guvner]

Re: Warning horn on 1991 88 HP...

How much of a fight are the springs? Which stat did you go with and how much is the whole deal likely to cost me going to my OMC dealer...<br /><br />Thanks again for all the help... Guvner..

 

[DJ]

Re: Warning horn on 1991 88 HP...

Guvner,<br /><br />It's a trick, no doubt about it. Just take your time and keep your patience. You'll get it.<br /><br />I think the whole mess is probably less than $40.00.