Ok I'm brand new to this so sorry for any stupid things I might over look. I just got a 98 gtx limited 50 hours and a 97 gtx 40 hours . They have been sitting for about 2 years a mechanic said the gtx had a bad mpem but I found the guy pluged a few things in the wrong place and didn't put the negative coil wire back so I got that going with the hose. My real problem is the limited was running great with the hose after I put new gas some sea foam and good 2 stroke oil. I had water coming out of the 2 jets by the hook and around the impeller. When I put the limited in the water it ran great for about a half mile then shut down form high temp I pulled the engine cover off and smoke or steam maybe both came out for a while . After it cooled off for a few hours I noticed the heads were a little Discolored but I got it to fire back up but I turned it back off because I don't want to do more damage . I'm not sure what to start with any help would be appreciated thanks
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1998 gtx limited
- Thread starter Jr12
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- BiRkS_
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This just turned into a can of worms. To start off. Don't run either ski until you do everything on this list. Other members may add to this..
-Replace ALL grey fuel lines (if you have them) ,clean the fuel selector valve, and tank. Sea foam is horrible. get that shit out. The carbs have to come apart. little fuel filters get clogged from the insides of the grey fuel lines that deteriorate with ethanol in the new fuels.
-Replace the inline oil filter. What oil are you using? you need to be using API-TC FULL SYNTHETIC in this engine. XPS II full synthetic preferred. If you have anything else, drain it!
-You have a blockage somewhere and you overheated the engine. unhook the main cooling line from the head and backflush it to the jet pump, see if you can dislodge any blockage.
-Pull the spark plugs out and take a picture if you can.
-Do a compression test. You have a 951 cc engine. Should be around 130 psi. If under 120, its rebuild time.
-The 1997 may have a 951. (if the engine looks like the 98, it is) If not, its a 787. This was a rare prototype engine that year. Alot of things were problematic and were changed (carbs, exhaust, etc)
-If both engines check out, you should service the jet pumps (many threads on this) and grease the PTO boot.
By the way, welcome to the forum! Hope I didn't scare you, we can help you through any problems you may encounter along the road. Part of the fun is riding, other part is fixing!
-Replace ALL grey fuel lines (if you have them) ,clean the fuel selector valve, and tank. Sea foam is horrible. get that shit out. The carbs have to come apart. little fuel filters get clogged from the insides of the grey fuel lines that deteriorate with ethanol in the new fuels.
-Replace the inline oil filter. What oil are you using? you need to be using API-TC FULL SYNTHETIC in this engine. XPS II full synthetic preferred. If you have anything else, drain it!
-You have a blockage somewhere and you overheated the engine. unhook the main cooling line from the head and backflush it to the jet pump, see if you can dislodge any blockage.
-Pull the spark plugs out and take a picture if you can.
-Do a compression test. You have a 951 cc engine. Should be around 130 psi. If under 120, its rebuild time.
-The 1997 may have a 951. (if the engine looks like the 98, it is) If not, its a 787. This was a rare prototype engine that year. Alot of things were problematic and were changed (carbs, exhaust, etc)
-If both engines check out, you should service the jet pumps (many threads on this) and grease the PTO boot.
By the way, welcome to the forum! Hope I didn't scare you, we can help you through any problems you may encounter along the road. Part of the fun is riding, other part is fixing!
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SabrToothSqrl
Well-Known Member
also, NEVER run sea-foam or any detergent cleaner in a 2 stroke. you may have just removed all the lubrication from the engine... and possibly destroyed it 
also what is "good 2 stroke oil"?
Unless it's SEA-DOO XPS-II" or 100% equivalent as shown by the oil ratings, you will destroy that 951 engine.
also what is "good 2 stroke oil"?
Unless it's SEA-DOO XPS-II" or 100% equivalent as shown by the oil ratings, you will destroy that 951 engine.
Sportster-2001-951C-Stock
Well-Known Member
"Sea foam is horrible."
Yep, today's fuel quality is already questionable, don't add anything that might tip the scales. Only stabilizer, if you cannot remove the fuel during winter storage.
These motors need lubrication, fuel carries the lube in an emulsion, to the working parts. No fuel, no lube, thus it's important to kaaep the fuel system working 100%, if it's not running correctly, find out why before running it hoping the problem will fix itself.
Some additive that might cause the lube to fall out of the emulsion would at best, accelerate wear.
Your particular problem sounds like a restriction in the cooling system, could be anything from a misconnected cooling hose to possibly an engine cooling passage clogged with sand.
You need a copy of the service manual, in there you will find a wealth of information. I suggest becoming intimately familiar with this manual, place it under your pillow at night.
Also, check your overtemp sensor circuit, this should sound a warning if the engine temp is elevated above normal. The service manual explains how it operates.
My factory original 2001 951 pumps 137 PSI of compression on both cylinders according to my gauge. The earlier versions pumped higher pressures, best I can tell from my research.
Yep, today's fuel quality is already questionable, don't add anything that might tip the scales. Only stabilizer, if you cannot remove the fuel during winter storage.
These motors need lubrication, fuel carries the lube in an emulsion, to the working parts. No fuel, no lube, thus it's important to kaaep the fuel system working 100%, if it's not running correctly, find out why before running it hoping the problem will fix itself.
Some additive that might cause the lube to fall out of the emulsion would at best, accelerate wear.
Your particular problem sounds like a restriction in the cooling system, could be anything from a misconnected cooling hose to possibly an engine cooling passage clogged with sand.
You need a copy of the service manual, in there you will find a wealth of information. I suggest becoming intimately familiar with this manual, place it under your pillow at night.
Also, check your overtemp sensor circuit, this should sound a warning if the engine temp is elevated above normal. The service manual explains how it operates.
My factory original 2001 951 pumps 137 PSI of compression on both cylinders according to my gauge. The earlier versions pumped higher pressures, best I can tell from my research.
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Sportster-2001-951C-Stock
Well-Known Member
"I can't get flow through the one from the rave solenoid to the crank case"
If this is an 951, which I think it is, that is part of the air intake system as described in the service manual. That line isn't a cooling line, it's an crankcase pressure line that provides crankcase pressure(consisting of: fuel + air + oil in crankcase) to the RAVE's when the solenoid is engaged. The MPEM opens the solenoid, which passes the pressure to the RAVE's and fills the internal RAVE bellows to open the exhaust ports up wider. The MPEM does this somewhere around 5000 RPM, I think, can't recall exactly.
This RAVE pressure line has a check valve very near the crankcase nipple which should only allow flow of pressure in one direction, which is, away from crankcase. Make sure the check valve is working, you can blow through it in one direction only. It's installed so pressure in the crankcase flows towards the solenoid valve. Also make sure the short line from the crankcase nipple to the check valve isn't cracked or broken. If there is a leak there, air can be drawn into the crankcase of the rear cylinder (PTO cyl) and cause a lean condition, which will lead to engine damage.
You need a cooling system plumbing diagram to make sure everything is correctly connected, make sure to get the correct one for your year b/c the earlier models are completely different from the later models. This might explain why something's connected incorrectly.
Many parts vendors have these diagrams on-line.
If this is an 951, which I think it is, that is part of the air intake system as described in the service manual. That line isn't a cooling line, it's an crankcase pressure line that provides crankcase pressure(consisting of: fuel + air + oil in crankcase) to the RAVE's when the solenoid is engaged. The MPEM opens the solenoid, which passes the pressure to the RAVE's and fills the internal RAVE bellows to open the exhaust ports up wider. The MPEM does this somewhere around 5000 RPM, I think, can't recall exactly.
This RAVE pressure line has a check valve very near the crankcase nipple which should only allow flow of pressure in one direction, which is, away from crankcase. Make sure the check valve is working, you can blow through it in one direction only. It's installed so pressure in the crankcase flows towards the solenoid valve. Also make sure the short line from the crankcase nipple to the check valve isn't cracked or broken. If there is a leak there, air can be drawn into the crankcase of the rear cylinder (PTO cyl) and cause a lean condition, which will lead to engine damage.
You need a cooling system plumbing diagram to make sure everything is correctly connected, make sure to get the correct one for your year b/c the earlier models are completely different from the later models. This might explain why something's connected incorrectly.
Many parts vendors have these diagrams on-line.
I'm going to pull the exhaust today after work so I can get to the check valve because I can't blow or suck air through the line and also check the oil line to see if it's clear . I'm not sure how the 951 motor pulls water out of the lake to cool it down so I'm goin to do some more reading thanks guys for all the help I'm new to this and I don't know anything about it but want to learn
Sportster-2001-951C-Stock
Well-Known Member
Man, on mine the RAVE air pressure check valve is pretty easy to get to, it's in the hose a few inches from the lower rear corner of the crankcase, cant imagine how it's be tough to get to.
The cooling system doesn't pull water from the lake per say, there's a port inside the jet pump just behind the impeller that water is forced into by the pressure developed by the impeller. This water goes to the cooling system. The jet pump provides the cooling water.
The cooling system doesn't pull water from the lake per say, there's a port inside the jet pump just behind the impeller that water is forced into by the pressure developed by the impeller. This water goes to the cooling system. The jet pump provides the cooling water.
Sportster-2001-951C-Stock
Well-Known Member
Yeah, you might be able to find a good used set of 951 RAVE assemblies. Look the base housing over carefully for wear around the blade shaft bore, and of course the condition of the rubber and plastic parts such as the pressure bellows and o-rings. Pay close attention to how it comes apart so you can put it back together correctly. They're really simple but I can see how something so simple can deceive and you don't want to be paying to replace new parts due to a simple mistake, so pay real close attention.
I can barely suck through my rave pressure check valve, might want to use a mighty-vac brake bleeder for that if you've got one. You said it ran like a scalded dog before it melted down, those raves had to be working because you won't have strong top end if the exhaust valve ports aren't opened up by the rave blades retracting up into it guide housing area. When the RAVES are at rest in the down position, they block the exhaust ports so the engine can idle, but once you get up into the power band the pressure from the solenoid fills the rubber RAVE bellows and pushes the RAVE's up, opening the exhaust ports.
Concentrate on resolving the cooling issue and go from there, obviously melted stuff will need replacing. Hopefully the engine doesn't come apart from being overheated, some bearing races in some of the engines were plastic, so the bearings might come apart if the races are ruined. If it starts making scary rattling sounds you might want to stop b/c crankcase housings are expensive and a broken rod will do all kinds of damage to anything it can reach. That overtemp buzzer should have been screaming it's head off at you.
Good luck!
I can barely suck through my rave pressure check valve, might want to use a mighty-vac brake bleeder for that if you've got one. You said it ran like a scalded dog before it melted down, those raves had to be working because you won't have strong top end if the exhaust valve ports aren't opened up by the rave blades retracting up into it guide housing area. When the RAVES are at rest in the down position, they block the exhaust ports so the engine can idle, but once you get up into the power band the pressure from the solenoid fills the rubber RAVE bellows and pushes the RAVE's up, opening the exhaust ports.
Concentrate on resolving the cooling issue and go from there, obviously melted stuff will need replacing. Hopefully the engine doesn't come apart from being overheated, some bearing races in some of the engines were plastic, so the bearings might come apart if the races are ruined. If it starts making scary rattling sounds you might want to stop b/c crankcase housings are expensive and a broken rod will do all kinds of damage to anything it can reach. That overtemp buzzer should have been screaming it's head off at you.
Good luck!
Ok so today I got the guide I needed for the rave valve put it all together did a compression check the cylinder that's discolored has 125 and the other has about 140 I didn't think that was good but I decided to start it. After it started I can rev it but it won't idle and seems to bog when I rev it . I noticed a little rattle but from what I read that's normal. Since it wouldn't idle me and a friend decided to pull the head off and check the cylinder walls . After we got it off we looked at the water intake and it was clogged with something that looked like detergent. I followed the line back and it goes to the main pickup so that would explain my over heating problem . The pistons seem good they both wiggle the same and the cylinder walls seem good. I'm not sure where to go from here maybe just buy a new head gasket put it on and do a compression check to see if it's even after that and that rattle keeps sticking in my head. Any help would be nice thank you very much for taking the time to read my post
Sportster-2001-951C-Stock
Well-Known Member
Since the cylinder looks good with no aluminum transfer, I'm wondering if a ring collapsed from overheating?
SabrToothSqrl
Well-Known Member
a yellowish color on the engine indicates it was overheated. Usually lack of lube or a part failure. (or cooling loss).
your 125 vs 140 indicates the engine shot. Go no further. a 10% or greater difference between them means the engine is shot.
Have the ENTIRE engine rebuilt. Only then will you have a running ski. Anything else you do will be a complete waste of time and effort.
your 125 vs 140 indicates the engine shot. Go no further. a 10% or greater difference between them means the engine is shot.
Have the ENTIRE engine rebuilt. Only then will you have a running ski. Anything else you do will be a complete waste of time and effort.
Okay so I pulled the head off and found it was very pitted where the gasket sits on it. The cylinders and the pistons look good. I'm planning on getting a new head, crank rebuild kit, piston rings and gasket kit. I've talked to a few guys around where I live that are familiar with these motors and they said that's all I should need. I plan on ball honing the cylinders just in case thanks for all the help
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