Boat trouble

[Jazzbay]

I have a 1996 Bayliner jazz sport jet 120 xr. It will run on the trailer but won’t start in the water. I’ve changed the stator,trigger swim,starter,battery,rebuilt the fuel pump,cleaned the carburetors. Did a compression test 115-120 on all cylinders. I’m at a loss!

 

[jdkaeser]

How old is the fuel? I was reading a post online with a guy who had a similar problem. Turned out to be bad gas. It was just bad enough that the added back pressure from the exhaust and impeller did not allow the fuel to vaporize. He drained and flushed the lines and it worked. He even had stabilizer in the fuel but it still happened. Could be that or if you have water in your tank and the boat sits differently in the water vs on the trailer the pickup is sucking the water vs the gas in each scenario.

 

[Julian]

What @jdkaeser said, and also you didn't mention spark plugs...if they aren't new, replace them.

 

[Jazzbay]

What @jdkaeser said, and also you didn't mention spark plugs...if they aren't new, replace them.

Yes they are new to.

 

[Jazzbay]

How old is the fuel? I was reading a post online with a guy who had a similar problem. Turned out to be bad gas. It was just bad enough that the added back pressure from the exhaust and impeller did not allow the fuel to vaporize. He drained and flushed the lines and it worked. He even had stabilizer in the fuel but it still happened. Could be that or if you have water in your tank and the boat sits differently in the water vs on the trailer the pickup is sucking the water vs the gas in each scenario.

I pumped all the gas out and put 10 gallons of new gas. Spark plugs were replaced to.

 

[Seattle_Phaeton]

Sounds familar. Don't know if this is your issue but a few years back I had an 1992 Chris Craft and it quit out on the lake and it would not restart no matter what I did. I had to be towed in. I brought the boat home and it started and ran fine on the trailer. Multiple times and no problem. Waited a couple of days and tried it again and it started and ran fine. Decided to take it to the lake put it in the water and it would not start, so I load it on the trailer and more than a little frustrated I decided to try and start it on they trailer at the lake..... and it fired right up...... so I shut it off put it back in the lake and it would not start. By this time I am beyond frustrated.
I finally decided to take it to the shop they had the boat for a week and told me it was just a lose wire on the ignition switch. I just couldn't belive it but that was the problem. I guess the movment on the water was just enough to to cause it.
I hope this helps good luck.

 

[jdkaeser]

Yeah, sounds like you have tried all the right things. I'm thinking like the poster above, it must be an electrical issue of some sort. Unfortunately, electrical gremlins are the worst thing to figure out. Was it doing all of this prior to swapping all the things you mentioned? If it was, then I'd compartmentalize the areas of electronics and start with the helm if the problem was existing. It has to be something with the power going to the ignition or fuel pump if the starter is turning over but not firing. Like above, ignition switch is most likely. Then move to the battery area, then engine compartment as the things you changed are probably tight. Checking all terminals for loose connections.

 

[Jazzbay]

I changed the reeds and now it runs in the water. Now I can’t get full power and it runs decent for a couple minutes and then it falls on its face and stalls. Tried adjusting the timing but that didn’t help much. I thought I fouled a spark plug so I bought 4 new ones. It didn’t solve the problem. Pulled the bowls off the carburetors,everything was fine. Help!!

 

[gt5pilot]

What fuel pressure do you have at the bowls? Are you sure the floats are set at the right height and not sticking? No cracks in the floats? Sounds like a DCOE Weber issue I had on a racecar - it would run fine for a bit until the float started taking on fuel and then the float would sink and shut off the fuel flow.