Higher rpm with seat off

gtx di · 08-06-2009, 09:37 AM

Bill why when i had the seat off on the ski to test the water regulator yesterday would the ski run 200 pms higher and 4 miles an hour faster than when i had the seat on?
6120 and 48 with seat on.
6380 and 52 with seat off.
Any ideas? It was a calm day and no boat traffic when i did both runs.

Bill O'Neal · 08-06-2009, 01:49 PM

Slight exhaust leakage or gasoline fumes in the engine bay will make the motor run too rich, killing max rpm. The only other possibility is no fresh air, or very little fresh air, is entering the engine bay.

gtx di · 08-06-2009, 02:24 PM

As far as fresh air not making it into the engine bay what do i check? I will pull the seats off later today and check for an exhaust leak. The other ski had a broken band on the exhaust but i fixed it. It did make a slight difference in rpm too. I did not see anything that was obvious. No smutting up of the engine bay or anything.

Bill O'Neal · 08-06-2009, 07:31 PM

Even a tiny exhaust gas leak will kill rpm. Can you run up a hill breathing carbon monoxcide ? Your motor can't either.

Not much to check for fresh air if the vents are not blocked off.

gtx di · 08-07-2009, 09:16 AM

Thanks again Bill. I will check it if i get a chance today. This is a great site with a great group of people willing to help!!!

gtx di · 08-10-2009, 11:38 AM

Bill i checked all of the exhaust and found no leaks. I ran the ski hard for 10 minutes or so and stopped and pulled the seat. No fumes whatso ever. I made sure all of the connections were tight and checked using my hand to see if i was getting any smutting around the connections. All of them were clean. Where does the ski take in outside air? Also i pulled the tops off of the rave valve regulators and they have some gunk built up on them. You can still pull the raves up freely. Is it normal to have a build up inside the regulator where the spring is or is that a sign of something wrong? I also checked for air leaks and found none of them either. Thanks again Bill for all of your help.

Bill O'Neal · 08-10-2009, 02:09 PM

I do not know what yu mean by "build up " as some wet black residue is normal inside of all rave valve diaphrams.

There are big black hoses attached to ai inlets. Look up under the hood.

gtx di · 08-10-2009, 02:33 PM

That is exactly what is inside. Just wet black residue.