95 GTX bogs down easily

[Tiger]

1995 GTX (657), new engine from SBT (40 minutes on engine). I had a buddy of mine that works for a local Sea-Doo dealer install the engine for me. He cleaned the carbs and all before installing them on the new engine. Well, I finally got the idle set right so that it doesn't kill while idling, but it still won't start in the water. I have to set the pump up on one of the trailer bunks to get the prop out of the water, then once it's started, push it back in. Also, putting the ski in reverse or neutral will make the ski kill, unless I'm on the throttle.

With a paddle on board, I continued the break-in process, and, as long as I didn't let it idle for too long or put it in reverse, the ski never died. It ran great actually. It's just starting in the water, or reverse/neutral at idle that is the problem.

Any suggestions? I'm going back to the landing today with the guy who helped me install it, but I'd like to get some ideas to try so that we're not wasting time on something that isn't the problem. Thanks.

[Bryan Glynn]

It definitly sounds like a carburation issue. I can't say for sure, but knowing how most dealers do carb jobs, yours may have been 'cleaned', but were probably not rebuilt, with a quality rebuild kit including all new gaskets and diaphrams. A good carb rebuild will cost upwards of $100/carb, to have it done. If this was not done, you REALLY need to do it - your carbs are 6 years old! If you want to rebuild them yourself, and save some cash, we sell kits for $30 each, and have a step-by-step guide available here. After this is complete, they need to be tuned. It's hard to say what your exact problem is, if you are rich or lean, but I would wager a guess that you are running too rich. See this guide for detailed instructions.

[Tiger]

According to him, they were rebuilt. All new gaskets, diaphrams, and that little fuel filter. He even showed me the old ones that he pulled off to illustrate how they looked. Running too rich - would you say that's the low speed screw that needs to be turned leaner?

[Bryan Glynn]

If you are having a starting problem, yes, it's the low-speed circuit. I'm not going to specifically say lean or rich without seeing the plugs and being there to tune the craft - if you are really on the lean side and you lean it out even more thinking it's rich, you could easily seize the engine. You need to use the carb tuning guide to check your plugs, see where you're at and go from there.

[Tiger]

Well now I'm starting to worry. I went to the landing with the Sea-Doo mechanic yesterday, showed him what my ski is doing, and even he has no idea what it could be. While we were there yesterday he adjusted the carbs, but to no avail. The ski cranks up fine out of the water, but when I back it in, it dies. I even put it in so that the pump was on top of the water (not in the water) and it would crank right up. But as soon as a vacuum was created and water started shooting out of the nozzle, it would die.

I know this sounds like an idle speed issue, but to get it to where it will idle in the water, its revving 4500+ out of the water. The ski also runs great when you are in the water and cruising. There's no bogging, no delay, cavitation, nothing. Just runs like a dream at higher-than-idle speeds.

Any suggestions before we start pulling the pump out, carbs out, etc. to try to find the gremlin in this ski? Thanks.

[Bryan Glynn]

Well, it sounds like you probably need to find a tuner that knows how to tune carbs.

It still sounds like you are too rich. Here's what you need to do:

Reset both your low-speed screws all the way in. Back them out 1 1/4 turns. Turn your idle screw all the way out. With the craft out of the water, start it up and set the idle to 3000 RPM.

Now with the craft still strapped to the trailer, back it into the water, and start making adjustments to the low-speed screws, according to our guide. Then set the in water idle to 1500 RPM.

This boat is stock, and you haven't rejetted your carbs have you?

[ March 06, 2001: Message edited by: Bryan Glynn - SBT Webmaster ]

[Tiger]

Right. Stock. One thing I forgot to mention is how the plugs looked. They were brown, and wet (not dripping but wet). I will try your suggestion this afternoon. Thanks for the help.

[raider1100]

its good that you have a brown colored plug
but they shouldnt really be wet. Your high screws should be set to 0. the low speed screws should be at 1 1/4 + or - a 1/4. So what you want to do is make sure your highs are turned all the way in and your lows are at a starting point of 1 1/4. Now also you may want to check for a air leak. you can start it on the trailer with a hose hooked up to the flush kit and then use a can of carb cleaner to spray around the intake of the motor and around the carbs. if the motor bogs down or revs up there is your leak
Rob [img]smile.gif[/img]

[Bryan Glynn]

Ahhhhh....don't ever spray carb cleaner on the outside of your engine unless you want to remove your paint (then you get to repaint it unless you want it to oxidize)! You can use propane for checking for leaks, and the engine will always rev up when you find one. The easiest way of doing so is to use a propane torch with tubing on the end to direct the flow.

[Tiger]

Oxygen? I'm not going to try it, but isn't Oxygen part of the whole internal combustion process anyway?

[raider1100]

You can use starting fluid also. But I guess propane works. never tried that
Rob

[Bryan Glynn]

No, you shouldn't because it will strip the paint. You need to use a flamable GAS, not LIQUID to check for an air leak. Spraying gobs of starting fluid all over your paint and into your hull just to use a little of the flammable fumes and propellant is not a good solution. And please do not post to use Oxygen again - that is just downright dangerous advice!

[Bryan Glynn]

Yes, but in VERY small percentages, not in 100% doses like Raider suggested (I deleted the post). Long story short, 100% oxygen will let ANYTHING burn, and do so VERY fast and VERY hot. Dumping 100% oxygen around a running engine will result in a VERY large explosion. I used to work for a medical oxygen company. One of the more 'exciting' explosions resulted from an old fart smoking while on her oxygen (9 of 10 patients were on it due to emphysema, etc - and STILL smoked), the oxygen let everything around her burn and explode. The three tanks she had in her apartment led to her apartment and the two next to hers, along with the roof of the building being blown apart.

[Tiger]

Problem Solved!!! It turned out to be the o-ring between the engine and the rotary valve cover. While it was making a secure seal, the o-ring was too thick and made a small gap between the cover and the engine. Replacing with a new o-ring did the job. No more gap, and the engine runs, starts, and idles with no problems.

Thanks to everyone on this group that helped me out. It's such a relief to finally have this taken care of! :D

Clint

[ April 02, 2001: Message edited by: Tiger ]

[SteveCLT]

The dangers of oxygen and fire!!!
How to start a charcoal grill in 3 seconds.

WARNING: an ignition source, such as a lit cigarette or one glowing coal, must be present before pouring on the LOX. If charcoal is PRESOAKED in LOX first, an explosion will result. One briquette presoaked in LOX is approx equiv to 1 stick of dynamite.