98 deadoo gtx overheat

[lexer440]

I picked up this machine for $500 with the intention of rebuilding it over winter. never done this before but i am very familiar with outboards so not a total novice to two strokes. It heated up enough to discolor head a little and melt a couple of plastic hoses lucky enough to be touching it and a local marina had taken off the heads to view piston damage and they were left off for a few weeks, they determined it would need a rebuild. Pistons look good, pretty much what I would expect to see, maybe a little blacker. I turned motor over and everything seemed to run smooth, new seals on the head, replaced the plastic hoses that melted and put the machine back together and did a compression test, found compression good so I gave it some gas and oil and fired it up. seems to run well and idles at around 2000rpm on hose. My question is, have I been really lucky or should I be looking deeper?

 

[mphy98]

Re: 98 deadoo gtx overheat

What was the root cause of the overheating? That would be my 1st thing to look for. Sand plugging up the water jackets?

 

[lexer440]

Re: 98 deadoo gtx overheat

I am trying to determine cause. water jacket seems clear but not fully checked out yet. No oil in tank but there was oil in pipe so maybe it did not run out. Speaking of oil, it was everywhere, bilge was covered in it and right up front too when i removed storage bin, clean oil at that, trying to clean it up and determine if was an internal leak somewhere. Apparently the last people to use this machine had borrowed it and returned it broken, obviously denying any wrong doing but who knows. anyway, it was cheap and i have the whole winter.

 

[arks]

Re: 98 deadoo gtx overheat

Overheat could've been sand or even seaweed blocking the intake, hard to know for sure.
Before taking it apart, I'd test it under load and see how it performs.
Cross your fingers; maybe you'll be lucky!

As far as the oil, I have a 97 GTI that had a similar problem.
Turns out the oil tank plug had worked loose and dumped half the oil in the tank.
I suspect that's the reason for oil in your bilge. I replaced the band around the plug and solved the problem.

 

[lexer440]

Re: 98 deadoo gtx overheat

Cooling system clear and intake and jet pump are good. So far the only thing i have found is a totally pooched rave valve on front, (Closest to handlebars), cylinder. The exhaust valve part is blistered and the red rubber spring seat is melted. Diaphram was good. Which do you guys think most likely - Cause of overheat or result of overheat? The other cyl's rave valve is good, no signs of stress.

 

[kmarine]

Re: 98 deadoo gtx overheat

I have a 98 gtx and Have also had cooling issues in the past. Is this a 951 engine? I suggest looking at ebay fo a set of rave valves I bought a used set for $25 a couple of years ago. Make sure to clean them and check for melted gaskets. They are real easy to replace, while at it wire brush the valves it is suggested they are done every 100 hours. be sure to check the rubber hose after the pipe. When overheating they are known to melt leaving water and ehaust in the bilge starving the engine for oxygen. also check the regulator on the water box behind the exhaust pipe. the holes in this valve are small and can clog up easily. do not overtighten. the threads are known to srip out easily. on your fisst few rides verify regularly that you are not overheating and check regularly under the seat. Hope you have lots of fun.