Runs fine out of water but not in water???

[hi5]

Ok this has been driving me crazy!!

I have a 96 HX with the 718. I was having trouble getting it to start (has been sitting for a year) . Anyway I got it to start, took it to the lake and it ran great for about 20 minutes then it just died. Then it would not start.

I charged the battery up then tried starting it out of the water and it would turn over but sounded sluggish. So i set the mix on the carbs and not it will start and run out of water with a garden hose of course. But everytime i take it to the lake it will not start once in the water. It tries and will start but won't throttle up or idle. But once I take it out of water it works fine.

Could this be a battery issue...i.e. not enough amps to crank everything and the pump or whatever that sucks water in?

One of the cylinders has low compression would this be the cause? Not sure what to do and would really appreciate some input.

Thanks.

 

[JPX]

What does low compression mean? My 96 HX is running about 155/150 - with MANY hours on it. The big thing is if they are vastly different between the two cylinders.

Compression problem would certainly point towards a condition where the piston rings are worn and or the cylinder wall is scored. Usually denotes itself in one cylinder - and probably from a lean fuel condition in that cylinder.

Which leads to the most likely REAL reason for your problem......fuel delivery.

 

[hi5]

Well if i remember the compression test was 150 in the front and 65-70 in the back.

You say fuel delivery.... what would most likely be the culprit? fuel pump, fuel lines, air,

Thanks

 

[JPX]

Sorry, I got kicked off the computer in the middle of that thought.:driving:

There is no fuel pump as you may be thinking of like modern fuel injected cars. The pumping action is done by the MAG carb through the fuel block and the pulsing of the engine.

I have these suggestions for the fuel delivery problem.....but with such an imbalance between the cylinders' compression, you are already looking at a top end rebuild.

Easy, but limited chance of success guide:
1. Clean out spin on fuel filter
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.
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.

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 and clogs the carbs.
2. Remove the carbs and disassemble for cleaning the internal filters.
3. Better yet, plan for rebuilding the carbs
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.

Click the link on my sig below to see what the more complicated guide looks like in pictures!