SportJet 120 fuel issues

[wavecutter9916]

Hello, I am new to the site. I just recently purchase a 1997 Wave Cutter 13ft jet boat. The first time we started the boat it would just flood out. I cleaned the carbs and rebuilt them with carb kits. Put it in the water and it would run fine at idle and get up on plane fast but then would bog. RPM?s would go up to 6000 full throttle for ten second the drop down to 4000 then it would bog or stall. It was like it was not getting fuel. Once the carb bowls fill back up it would do the same thing. If I put my hand over the lower carb for a second while moving the RPM?s would go back up.

I am guessing it needs the fuel pump rebuilt

Took the carbs off and checked the reeds. Two of the reed were bad so I replaced them. But still getting the same response.

Also checked the electrical system, Everything looked spark on all 4 cylinders new plugs ect?.

Any help would be great!

 

[Oode]

Re: SportJet 120 fuel issues

Sounds like a fuel pump to me... best to check by pulling the fuel line off and runing it to a jar, word is if it pulses, you need to rebuild. It's a pretty straight forward job, (assuming I have actually done it correctly, see my other posts..) if you follow instructions in manual.

For curiosity, where you able to find individual reeds, or did you have to replace the whole reed block???

 

[wavecutter9916]

Re: SportJet 120 fuel issues

Sounds like a fuel pump to me... best to check by pulling the fuel line off and runing it to a jar, word is if it pulses, you need to rebuild. It's a pretty straight forward job, (assuming I have actually done it correctly, see my other posts..) if you follow instructions in manual.

For curiosity, where you able to find individual reeds, or did you have to replace the whole reed block???

Oode, Thanks for your responce... I will try that tonight. I had to replace the reed block.

 

[wavecutter9916]

Re: SportJet 120 fuel issues

I checked the fuel pump it was fine?. Not sure what to do next. Any help would be great!

 

[Oode]

Re: SportJet 120 fuel issues

Your problems sound like some of my problems that I'm still working on, but one thing I found was my sparks look good, but my stator is out of spec, and may be my problem. You should ohm out the 4 stator leads and see what you get, even if you have a spark, it may be the problem.

It may also help to put a section of clear tubing and an inline fuel pressure gauge on the fuel line, that way you can tell exactly what is going on..

 

[wavecutter9916]

Re: SportJet 120 fuel issues

Thanks, That was going to be my next step..... Check all the coils and stator. I will let you know how I make out.

 

[kend301]

Re: SportJet 120 fuel issues

check your stator and electrical system as posted in the forst post in the forum , "soprt jet info and basics " post the results . You covering the lower carb and it picking up RPM tells me that is where your problem is , Check throttle linkage adjustments and look down the carbs at WOT and be sure all the butterflys are horizontal and not past wide open . post up results and we can go from there .

 

[wavecutter9916]

Re: SportJet 120 fuel issues

It was the lower carb not getting enough fuel. Removed the carburetor and let it soak and cleaned with air. Runs great now!

 

[kend301]

Re: SportJet 120 fuel issues

Glad to hear it , now do it to the top carb as it si not far behind , Trust me on this one

 

[wavecutter9916]

Re: SportJet 120 fuel issues

Ok? Have a new problem. The boat gets up on plane and RPM?s go up to 5500 for about 10-15 seconds. Then they drop down to 4000. I pulled the carbs again. Rebuilt the fuel pump and replaced all fuel lines. Not sure if it is a fuel issue anymore. One thing I did notice when replacing the fuel line on the gas tank. The out let connection was ? inch not 5/16 like the rest of the connections. Would that restrict the fuel flow?