Just got done replacing the carborators and the rear piston (clips, bearings, washers and Gaskets-head, Cylnder and Carborator). Went riding today and the ski seemed to run ok, but slow 65.8-GPS. The last part of the ride the ski would run from 64-67 back to 64 back to 67 at WOT-these are speedometer #s. It felt like the Power valves were cycling, so I took off the PV cover off the PV motor and it was operating fine. Got home, did a plug chop to read the plugs. The first two plugs the ceramic insulator was greyish white with the metal blackish. The last plug insulator was ORANGISH Brown-all over the inslulator. A compression check showed 150, 150, 148. The top of the rear piston was light grey. Any ideas??? Thanks for any help.

Sounds like your running lean in the first 2 holes.Get a tach and check your R's.Running too rich or lean will take away performance and speed.

I am going to richen 1 & 2, but I do not feel that this is the problem. The rear cylnder and the orangish color and the inconsistant running is my main concern, just don't know what it is?

Whats your rpm's? Also,your getting 150 psi,what guage you using? Just wondering because i don't see an aftermarket head in your mods list.Is it a box stock 14/20?

I have been having trouble getting the new Tiny Tach (commercial type) to work worth a dam-so I do not have an accurate RPM reading. I have a shaved (by Riva) head. The 14/20 was depitched by Island Racing for my ski. Sorry for the delay in reply, been working on richening the carbs. Looked at previous posts and did not see a orange plug color-at least nothing close to mine.

Your compression is even,thats a good start.Need to get that tach fixed.

There is no fixing the piece of garbage Tiny Tach (new version). This tach is a commercial tach and was never meant for jetskis. This is my second one (returned the first). Even if you program it for 180 and reprogram it for 180 it still gives you readings of 8000+ rpms. What a piece of garbage, or should I say a waste of money buying something that was never meant for the purpose I used it for.

nc - I had the same problem initially with the new tt; high rpm readings.I spaced out the wraps around the plug wire so all the wraps covered about 3-4 inches down the wire from the plug cap.Been great since.

Ward

HotHMR, thanks, I eat my words. Your recommendation worked. You REALLY need to spread out the loops far apart to correct the problem. Thanks, now if I can only figure out why the ski seems like the PV are cycling when they are not I will be a happy boy (you can feel it in the ski-pretty bad). Thanks.

nc- Glad it worked Now;I would be very careful as it sounds like you are describing a "lean surge" condition. Have you bypassed the fuel selector or at least running on reserve only?It's just a hunch, but look at fuel supply or delivery issues. Do a search and there is a lot of information on bypassing the fuel selector and multiple feeds.

NC,

I believe the Hamr is dead on. I've had the same problem as well. The give away was that the piston tops started to cut a little crater in #1 and #2. It is a fuel delivery problem. You are not getting enough fuel in certain conditions.

Like the Hamr suggested the cheapest (and simplest) is to bypass the fuel selector with your original fuel line. Then you carry it to the next level by running your reserve line as a second line to the carbs. Both lines come directly from the tank, and each line has its own fuel filter. Run a 1/4" "T" on the fuel supply line between carbs #1 and #2. You won't have a fuel problem again.

After I did this, all of my plugs showed color and tuning was much easier. You are also going to have to extend the normal running dip tube to match the length of the reserve dip tube inside the tank. I would realy bet money that this is your problem.

You know, I'm not usually this insistent about stuff, but I lost two cylinders because of it. I HIGHLY recommend that you do this mod!!!

Salty

this thing is killing me!!!

Did it look like this?

First thing to do is change the fuel filter. It probably has junk in it. If that doesn't do it, then do the fuel line mods.

First thing to do is change the fuel filter. It probably has junk in it. If that doesn't do it, then do the fuel line mods. Check to make sure that the fuel lines that screw into the carbs don't have any obstructions in the inlets.

Hothmr and Salty, you are probably exactly right. The carbs I purchased were set up to by pass the fuel switch and both lines ran directly to the carbs. I put back to stock form, since I really try not to modify too many things that are not necessary-I was certainly wrong on this one. I will put back to bypass the fuel switch and have both lines run to the carbs after I take off that $%^& anaconda pipe for the hundreth time. Thanks For the help.
WOW it was orange, but not that bad (close tho). I will also change the filter. THanks.