2001 gti starts on trailer and not in the water
- Thread starter Cheflen
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Cheflen
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Rebuilt the bottom end AND new rings with honing the cylinders, reused the pistons. Crank siezed so I put a new crank in. Sorry I should've clarified that. Haven't gotten a compression test yet but would a worn rotary valve bring the compression down? Also I know it would cause a hard start but this is a NO start in the water and it starts right up in the first crank on the trailer
Need to know your compression number.
Off timed rotary valve would affect the numbers but would still build up slowly.
To much gap or wear wouldn't hinder the compression but yes hard to start.
Air leak maybe.
Off timed valve, how did you end up after setting it ? About 1/2 inch below the mag port ?
ignition timing off, did you replace the outer crank seals?
Did you do anything to the carb ?
Does it have an accell pump or not?
What is your idle set to? 3k out of water?
Need some more info.
And maybe a video.
Off timed rotary valve would affect the numbers but would still build up slowly.
To much gap or wear wouldn't hinder the compression but yes hard to start.
Air leak maybe.
Off timed valve, how did you end up after setting it ? About 1/2 inch below the mag port ?
ignition timing off, did you replace the outer crank seals?
Did you do anything to the carb ?
Does it have an accell pump or not?
What is your idle set to? 3k out of water?
Need some more info.
And maybe a video.
Cheflen
Active Member
put the rotary valve at 65 degrees below the intake opening when the mag piston was at TDC
has new crank seals along with a new crankshaft.
Haven't touched the carb cuz it ran before the crank siezed. Idle was set high to keep it running
If you set it 64 degrees below the bottom of the intake port it’s wrong. It’s 64 degrees below the top of the intake port.
But don’t mess with anything till you check compression.
If your cylinders were worn and you honed with new rings you might have made your compression even worse and now it won’t start in the water.
With all the stuff you did you would have been better off boring the cylinders to the next oversize and new pistons.
But don’t mess with anything till you check compression.
If your cylinders were worn and you honed with new rings you might have made your compression even worse and now it won’t start in the water.
With all the stuff you did you would have been better off boring the cylinders to the next oversize and new pistons.
Cheflen
Active Member
Yes I meant 65 degrees below the top of the port
Cheflen
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All I did was use a ball hone on a drill to just clean up the cylinder walls and make a nice cross hatch, would that really kill the compression that easily? I didn't think I took that much off
Cheflen
Active Member
Yes sorry for the overload of questions before getting the compression test, still trying to get my hands on a tester. The 717s are supposed to have 150 psi correct?
Cheflen
Active Member
Here is an update: I haven't gotten my hands on a compression tester yet, but I got a new rotary valve in the mail, put that on and it started right up. I headed to the ramp and it started right up In the water and had good power (it was pushing my car around on the trailer) it was smoking a lot because I mixed some oil in the gas for break in, and I sprayed bombardier lube all over the spark plug holes along with the rotary valve opening because I wasn't sure how long the engine would be sitting. After running in the water for a few minutes, (I just had it idle a few minutes to burn the smoke off) it just died, and didn't start up on the trailer so I figured it was probably fouled spark plugs. I pulled it out of the water and after a few cranks it started up so I backed it back in and no start in the water again. I didn't have backup spark plugs and I won't be going back to the water until tomorrow with new plugs. Is fouled plugs the culprit of this?
I also rented the auto zone compression tester and it said 90 psi in each cylinder, but I read the reviews saying that it always gave 90 psi so it's a bad tester.
My question is, is it the fouled spark plugs that will start the engine out of the water but not in the water? I had power in the water before it died, everything revved up good
I also rented the auto zone compression tester and it said 90 psi in each cylinder, but I read the reviews saying that it always gave 90 psi so it's a bad tester.
My question is, is it the fouled spark plugs that will start the engine out of the water but not in the water? I had power in the water before it died, everything revved up good
Cheflen
Active Member
Well how come it had the compression right before it cut? Also I just started it on the trailer and it had plenty of power. It's running very rich and the plugs seemed bad. The battery also needs a good charge, so I hope all of this will make it run. Obviously I will need a compression test, I'm trying to figure that out I just didn't know if I have a different scenario than low compression as it did start right up in the water and had power
Cheflen
Active Member
Well that's why I'm saying it had plenty of power in the water, it ran good for about 10 minutes and revved all the way up with good power, I don't think it has bad compression
Cheflen
Active Member
Another update, I am borrowing a good compression tester tomorrow, but this time I threw new plugs in and decided to try it in the water again. It started up after a few cranks and ran good, pulled very hard, then as soon as I shut it off it wouldn't start again. The ski was smoking a lot when it was running so I think it's a bad oil mixture, the plugs looked pretty black, so I turned down the low speed screw and it would sputter in the water instead of not firing at all before. I pulled it out of the water and after a few cranks it started up again. Is this a bad oil mixture? I have the oil injection on along with about a half a quart mixed into the gas along with a little over a half a tank of gas. When I had the shop install the rotary shaft they disconnected the oil pump cable so I'm not sure if I don't have it adjusted properly and am making it run too rich on oil.
I know everyone will probably say I need a compression test first but that is tomorrow and I'm anxious to see if anyone knows any other possible solution. Any response helps
I know everyone will probably say I need a compression test first but that is tomorrow and I'm anxious to see if anyone knows any other possible solution. Any response helps
Cheflen
Active Member
I've been reading the repair manuals and it states that scratches on the rotary valve cover can cause an engine idle to slow down and then stall. But does this affect starting back up again? Can this be my problem? I do remember some small scratches on the cover but nothing too bad
Dr Honda
Well-Known Member
You still haven't given us a needed bit of data... A good compression number.
Also... when you honed the cyl's... what tool did you use? Did you use a machinist's hone, a ball hone, or a spring loaded hone with flat stones?
When you put the engine back together... did you check the squash band?
Scratches in the RV cover can cause issues... but I've seen some ugly ones run just fine. Did you check the clearance?
You were talking about adjusting the low screws. STOP !! If you rebuilt the carbs, just set them to the factory spec. ALL SEADOOS WILL RUN AT THE FACTORY SPECS. Also... it's a 2-stroke... it's going to smoke cold. it's oil that isn't burning. It sounds like you are fouling plugs quick. If you were over oiling, or over fueling to the point that it sounds... it wouldn't run. (Way rich) But low compression, and/or improper squash band would foul plugs as the combustion isn't getting hot enough to clean the plug.
We know it fires... so it's close. Also, you assumed the compression tool was bad... did you check it on a known good running engine?
Also... when you honed the cyl's... what tool did you use? Did you use a machinist's hone, a ball hone, or a spring loaded hone with flat stones?
When you put the engine back together... did you check the squash band?
Scratches in the RV cover can cause issues... but I've seen some ugly ones run just fine. Did you check the clearance?
You were talking about adjusting the low screws. STOP !! If you rebuilt the carbs, just set them to the factory spec. ALL SEADOOS WILL RUN AT THE FACTORY SPECS. Also... it's a 2-stroke... it's going to smoke cold. it's oil that isn't burning. It sounds like you are fouling plugs quick. If you were over oiling, or over fueling to the point that it sounds... it wouldn't run. (Way rich) But low compression, and/or improper squash band would foul plugs as the combustion isn't getting hot enough to clean the plug.
We know it fires... so it's close. Also, you assumed the compression tool was bad... did you check it on a known good running engine?
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Cheflen
Active Member
I haven't checked the compression tool on a different engine, I saw every review on it say it never went over 90, it's the auto zone rental tool, I rented it and brought it out to the parking lot, tested it a few times, never went over 90, so I returned it. I could tell the tool was cheap. I'm going to be using a snap-on compression tester today so I will get back with those results, I'm just anxious to find out the problem and hoping that I don't need a top end because that's not cheap. When I test the compression, do I leave the other plug in or take it out?
Cheflen
Active Member
Also I used a ball hone, I did not take much off as I knew I was keeping the same pistons, I only cleaned up the hone and made a nice cross hatch.
Cheflen
Active Member
Is there a way to test the squash band?
Cheflen
Active Member
So I got a good compression test, both cylinders are at 138 exactly, perfectly even. This is with a cold motor and it still hasn't been broken in. So now I'm not sure what the problem is, luckily I don't need a top end. The plugs are still covered in oil, I haven't run out the tank from last year with the stabil so maybe I should flush the tank? I also have oil mixed in with the gas. Any ideas would help
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