Engine issues.

[wink83]

I have a 1999 sea foo sportster 1800. Twin 717 rotax motors. My left motor I have been having issues with.
it will run great on land and with a hose hooked up. As soon as I back it into water it won’t start. It wants too but just won’t. I’ve changed plugs check all oil and fuel and still can’t figure out what’s causing this.

 

[Ckrawiec]

I have a 1999 sea foo sportster 1800. Twin 717 rotax motors. My left motor I have been having issues with.
it will run great on land and with a hose hooked up. As soon as I back it into water it won’t start. It wants too but just won’t. I’ve changed plugs check all oil and fuel and still can’t figure out what’s causing this.

Fuel delivery.....when were the carbs serviced last?

Famous Seedoo saying.....CHAMP on the trailer, CHUMP in the water......99.9% of the time it's fuel delivery to the motor......the carb(s) need to be spot on for these machines to function at full capacity ESPECIALLY on the water......

The motor spinning in AIR has very little to no load on it.....trying to spin in water is the real test....water is the load test for the engine/fuel delivery, etc.......

 

[wink83]

So I was wondering if it was the carbs. Or if the water box Muffler was allowing water to the motor.
as soon as I put it in the water one Motor runs great the other won’t even start. As soon as it’s on the trailer again. It pop’s right off.

 

[wink83]

I’m also wondering if there is a baffle or a flange in the water box allowing it to filll with water when I back it up into the river.
it was running great all day. Then towards the end of the day the left one wouldn’t start. Took it home changed plugs and runs great on the trailer and with a hose hooked up. Then again this weekend went to test it and backed it into the water and won’t start. Getting fuel and oil so I’m really stuck as to what can be going on.

 

[Ckrawiec]

Personally......when I was working on my '96 -787 engine......I could get her screaming on the trailer, no problems....as soon as she hit the water....would not start on the water.....kept wanting too, trying to, but NO DICE.

It took many tries and adjusting and tinkering until I had both carbs dialed in just right....now she starts on the WATER every time......it's a funny thing with these machines.

 

[wink83]

Personally......when I was working on my '96 -787 engine......I could get her screaming on the trailer, no problems....as soon as she hit the water....would not start on the water.....kept wanting too, trying to, but NO DICE.

It took many tries and adjusting and tinkering until I had both carbs dialed in just right....now she starts on the WATER every time......it's a funny thing with these machines.

See that’s what is confusing ran good as hell all day and then went to start it for the last run on the tube and it wouldn’t turn over.

 

[Ckrawiec]

See that’s what is confusing ran good as hell all day and then went to start it for the last run on the tube and it wouldn’t turn over.

You would be surprised at how (potentially) the tiniest speck of "something" can change the dynamic of the carb's behaviour......one minute working great, then falls flat on her face.

It happens....more often than you may think or want to believe.....everything has to be almost perfect....clean fuel, fuel lines, filters, carb passages, everything.....IF NOTHING ELSE, these machines will try your patience.....labors of love & hate simultaneously, especially the old two strokers.....

 

[AKnarrowback]

Do a compression check first. Easiest and fastest. Low compression will give you the same results you are describing. However, it usually doesn't change so abruptly so the chances of a carb issue are much more realistic.