I hate to ask but I searched before I posted 98 GTXL Compression Question

[RICHRICH36]

Ok, I searched and searched before I asked because I am sure that this horse has been beat many times but here we go.......Is 145/140 on a 98 GTXL ok??? It has had that compression for about two years and ran like a champ (at least to me). Took it out today and after about an hour (new plugs this year, snipped wires back) the RPM's would flucuate. In the range of about 1000rpm difference. I clean the raves every year (didnt do it this year though) pull the carbs every year and clean the filters. The water regulator seems to be fine (as far as I can tell) I am running 40:1 premix. The oil pump is blanked and looks still sealed. I guess the question is: Is there any way the 145/140 compression could be causing the flucuation in the RPM's???

[dsolie]

Re: I hate to ask but I searched before I posted 98 GTXL Compression Question

145/140 is great compression.. So that is not your issue.

When does the RPM change happen? Wide open, idle, only when warm etc?

[RICHRICH36]

Re: I hate to ask but I searched before I posted 98 GTXL Compression Question

WOT only, seems good at any other throttle position. Its not a rev limiter issue because it is going from about 6700 to 5700.

[dsolie]

Re: I hate to ask but I searched before I posted 98 GTXL Compression Question

Raves, water reg, reeds.. In that order..

No exhaust leaks?

[RICHRICH36]

Re: I hate to ask but I searched before I posted 98 GTXL Compression Question

Raves and water reg seem to be fine, I will check reeds, do you think it could be the reeds since it was fine for a little while then about after an hour on the water it started acting up???

[mstovenour]

Re: I hate to ask but I searched before I posted 98 GTXL Compression Question

The other posters are probably giving you the most common issues so I would start there first. I want to throw out two others that I personally experienced with my 98 GTX-L since it is not that hard to check for these issues.

The first problem that sounded similar to yours is that my starter came partially loose, just a little. The RPM variations only showed up at higher speeds because of the wave action. The ground from the battery is connected directly to the starter. The starter is then connected to the crankcase. The MPEM is grounded to the crankcase up by the mag. With the starter loose there was an intermitent battery connection to the crankcase and therefore the MPEM and mag. I tightened the starter and the problem went away. In the process I broke off one of the bolts. This causes the starter to come loose from time to time. So that I'm never inconvienienced at the lake, I installed a 12GA jumper that connects the battery ground lug at the starter to the MPEM ground lug at the mag. Problem solved.

The secod problem was much more serious. I'm replacing a top end right now because of it. I developed a small air leak in the fuel pump pulse line. It was caused by fuel/oil sitting in the bottom loop of the pulse line and slowly deterioriating the line from the inside out. The air leak came on slowly and was intermittent at first because a flap of fuel line would suck closed then sometimes open. The symptom that should have made me take it to the shop was that the ski would run away on the trailer. But the runaway was intermitent at first. Early on the ski would bounce the RPM at higher RPMs probably because of fuel flow. Then the ski would run like a dog on some days, so bad I would trailer it, then run like a champ on other days (probably the massive air leak). I didn't know to choke and full throttle a runaway. One day it ran away on the hose at home. Unable to kill it, I took the plugs off, turned off the fuel and went inside my house fully expecting it to throw a rod or sieze. It finally stopped after about 2 minutes and the pto carb had ice on it. I then pulled the pulse line out of a hunch. Problem solved. Fixing the damage is another story.