Do you have any of these symptoms on your carbureted 2-stroke engine?
- Low revs in water with throttle all the way on
- Okay revs out of water, but low revs in water
- Bogging when going from idle to full throttle
- Surging of revs
- Intermittent or sudden cutting out of engine when at speed
Then you might have a fuel delivery problem. Hopefully your use of the search feature in seadooforum.com has led you here!
First: confirm you already put new, clean, and properly gapped plugs and confirmed there is spark to BOTH cylinders. As this only costs $2/plug and a couple of minutes, you should do this before moving on.
For those of you with Seadoos made in the 1990s, you should expect to have some type of carb problems if you have the original gray fuel hoses. The hose breaks down internally and the residue accumulates in the filters.
I will break this up into two approaches since not everyone is up for a full fuel system rehabilitation and not everyone is satisfied with piece-meal fixes. Choose what is right for you.
Easy, but limited chance of success guide:
1. Clean out spin on fuel filter. Make sure the o-ring is there. Don't use carb cleaner or you will dissolve the filter's fiber mesh.
2. Try running your boat on RES - this would point to a clogged fuel selector valve.
3. Remove the fuel selector valve and clean it out with carb cleaner. Blow it out with compressed air in the ON and RES positions.
4. Change to new spark plugs. You should have already done that.
5. Pull spark plug wire from boot. Trim 1/4" off the tip of the wire. Reinstall to the boot and ziptie it back on.
6. Make sure your carbs' high speed adjuster is set to fully closed clockwise (zero). Set low speed adjusters to fully closed clockwise, then turn counterclockwise specific turns to your engine. Use the idle screw to set idle speed only - do not use low speed adjusters to set idle speed.
7. Check all fuel hose connections are tight and that the check valves freely blow one way, but do not the other (one above the fuel tank and one on the side of the hull from the fuel tank):More complicated, but high chance of success guide:
1. Remove all grey fuel hose (if you still have it) and replace with black automotive fuel hose. The grey stuff breaks down on the inside and clogs the carbs' internal filters. You'll need mostly 1/4" black automotive fuel hose (Coast Guard approved marine grade fuel injected hose is top of the line, but costly). Get 25 feet of it and about 30 stainless steel #04 hose clamps....no zip ties!
2. Remove the carbs and disassemble for cleaning the internal filters.
3. Better yet, plan for rebuilding the carbs
Here are some excellent resources for cleaning/rebuilding the carbs and setting them up properly:
- Make sure your carbs' high speed adjuster is set to fully closed clockwise (zero). Set low speed adjusters to fully closed clockwise, then turn counterclockwise specific turns to your engine. Use the idle screw to set idle speed only - do not use low speed adjusters to set idle speed.
4. Clean spin on external filter, clean out fuel selector valve.
5. Pull fuel baffle from the tank and check for any obstructions on the intake screen. If you have lots of junk in the fuel tank, siphon out the gas and suck out the contaminants, then refill with fresh gas. If your fuel gauge doesn't work or always shows empty, check out this link while you have everything in pieces Fix for Fuel gauge empty or light on when tank is full (fuel baffle/sender)
7. Check all fuel hose connections are tight and that the check valves freely blow one way, but do not the other (one above the fuel tank and one on the side of the hull from the fuel tank):
Note: This is primarily directed towards carbuerated 2-stroke models, but the principles apply to all gas engines. Those of you more experienced in the RFIs and 4-TECs feel free to chime in so we can include those specific guides on this thread as well.