Repair Advice Needed

[mhocken]

1994 XP - 5 Years Storage / Repair Decision / Compression Difference

First of all, what a great forum! I have learned a lot about my ski in the last week from vast collection of knowledge and experience contained in this forum.

I have a 1994 Seadoo XP. It has been sitting for 5 years. Took it to the boat ramp and ran it and it would bog down and stop with any throttle. Took the boat home, replaced the old fuel, replaced all the Grey Tempo(rary) fuel lines, and cleaned the fuel selector switch (I plan to replace it when the new part arrives). Took it back to the boat ramp and it would still bog down but I could get it to rev up if I very slowly applied the throttle. At times I would get a faint heat buzzer but it would go away in a few seconds (running lean?). Compression is 150 MAG and 120 PTO. Based on the info from this forum, my next step is to have the carb rebuilt. I took my ski to the mechanic this morning and he told me $250 to rebuild both carbs. I said OK and left. I got a call back from the mechanic and he tells me that my real issue is the difference in compression between cylinders and that my ski needs a top end rebuild. He told me the cost for both the top end rebuild and the carb rebuild would be $650 out the door. After some thought I gave him the go ahead to make the repairs. Did I do the right thing? Did I just order a top end rebuild that I did not need? Or should I have had the carbs done first and put off the top end rebuild? He told me that I would save in labor by getting them both done at the same time. Any feedback would be appreciated as I try to justify spending $650 additional $ on top of the $250 I have already spent on battery, fuel selector switch, fuel filter, fuel lines, plugs, shipping, my labor, etc. The ski is in good shape otherwise and I have owned it for 14 years.

Your opinion is appreciated.

Mike.

 

[chipmcod]

ya you might save an hour of labor and if it was me id ask what the compession was then take it somewhere else askthe same thing see if the first guy was full of crap and if he was then have the second peson rebuild my carbs and if he was honest see who is more credited and less expensive. just a thought always try the simple things first then learn how to do it yourself.

 

[mhocken]

I personally checked the compression prior to taking it to the shop using the techniques described on this forum. The readings were 120 rear, 145 front. The tech told me 120 rear, 150 front.

The real question is whether or not the 25-30lb. difference between cylinders is enough to warrant a top end rebuild. I have read on the forum that a maximum of 15% difference is recommended and my delta is greater than that. Most opinions I found recommend they be within 5% of each other.

I am curious to know what symptoms a motor shows when there is a difference of more than 15%. Lower top speed? Less acceleration? Hard starting? And how does running a difference in compression between cylinders contribute to component failure. My intuition tells me that the good cylinder is doing more work and therefore will experiences more wear and abuse. I would expect the motor to produce less power over time as the good cylinder wears out. My knowledge of these engines is very limited but growing thanks to the forum. I would like to know others opinions on why it is critical to maintain near equal compression on both cylinders and what happens when there is a substantial difference.