1996 Seadoo Challenger 787 Engine is having some running issue.

[frank.dimambro]

Hi
I have 1996 Seadoo Challenger with a 787 Engine and it's having running
issues. It starts off well getting out of the 5MPH wake zone but starts to fail
once you push the throttle beyond the half way mark. Initially it feels like
it's going to take off and it does but then it wimpers on not really accelerating
beyond the 15MPH mark.
The carb is set at the Challenger workshop manual settings which

Low speed screw is 1 turn out from completely closed.
High speed speed screw is completely closed.

The previous visit to the lake I did put in a fresh set of spark plugs and
for that visit to the lake it worked flawlessly.
I did persist with it and the boat eventually got up to speed, so then we
tried the towable and we got the same limited behavior.
It seems that every time we slow down the engine has difficulty getting
back up to speed. I eventually gave up and took it into the dock.
I did grab some video to let folks on the forum hear how it sounds
hopefully that will help me get some targeted help that will get this
boat going great. Looking forward to hear from you.
I've posted a video to Youtube that I hope helps give the sound the
engine makes when it fails, and will help folks in the forum give hints
on what to fix.

http://youtu.be/shoQprdo1-4

 

[LouDoo]

Does your boat still have grey tempo fuel lines? If it does they need to be replaced with back automotive fuel hose, and the fuel delivery system cleaned. I'm not going into great detail until we see if the lines have been changed.

Lou

 

[Robj]

Yep, as ^ Lou said above. You fuel delivery system needs work. I don't know if boats used the same fuel lines as skis, but you need to check. Once that is done, clean or rebuild the carbs. Running it like it is could cost you a motor.

 

[Coastiejoe]

Yep, as ^ Lou said above. You fuel delivery system needs work. I don't know if boats used the same fuel lines as skis, but you need to check. Once that is done, clean or rebuild the carbs. Running it like it is could cost you a motor.

I have read that the boats never used the Grey Line. That said, they are the same engine. I'd still be looking to make sure they were not there.

 

[frank.dimambro]

Does your boat still have grey tempo fuel lines? If it does they need to be replaced with back automotive fuel hose, and the fuel delivery system cleaned. I'm not going into great detail until we see if the lines have been changed.

Lou

Hi Lou, Thanks for the quick reply, The boat has the black fuel lines.

 

[frank.dimambro]

Yep, as ^ Lou said above. You fuel delivery system needs work. I don't know if boats used the same fuel lines as skis, but you need to check. Once that is done, clean or rebuild the carbs. Running it like it is could cost you a motor.

I was suspecting the fuel delivery, I've taken the carbs off before and cleaned then, and replaced the pump bits, but they
may have gotten clogged again. Is there any area of the carb that I need to take a close look at, or is this just something
that taking the carbs out and cleaning just fixes?
One last thing, thanks for the 'could trash the motor warning'.

 

[Robj]

I was suspecting the fuel delivery, I've taken the carbs off before and cleaned then, and replaced the pump bits, but they
may have gotten clogged again. Is there any area of the carb that I need to take a close look at, or is this just something
that taking the carbs out and cleaning just fixes?
One last thing, thanks for the 'could trash the motor warning'.

Clean or replace the small filters, clean the transfer ports. The transfer ports are the three small holes above the butterfly. You clean the, by spraying carb cleaner through the idle circuit. Check the condition of the diaphram. If you have a pop off tester, I would check the needle and seat as well, but I don't think they are causing your problem.

 

[frank.dimambro]

Clean or replace the small filters, clean the transfer ports. The transfer ports are the three small holes above the butterfly. You clean the, by spraying carb cleaner through the idle circuit. Check the condition of the diaphram. If you have a pop off tester, I would check the needle and seat as well, but I don't think they are causing your problem.

I took a look at the inline fuel filter that's before you get to the CARBs and it was full of MUD, I cleaned it out and put it back in place, I also have a spare set of cards which are all nice and clean, All I need now is to get some time on the lake see if that did the biz.

Thanks again for responding to my post, I'll let you know

 

[frank.dimambro]

Clean or replace the small filters, clean the transfer ports. The transfer ports are the three small holes above the butterfly. You clean the, by spraying carb cleaner through the idle circuit. Check the condition of the diaphram. If you have a pop off tester, I would check the needle and seat as well, but I don't think they are causing your problem.

I took the small filters out of each card and while there is some dirt the Magneto Carb filter it's not
completely clogged. The PTO carb filter is a lot more dirty.

I've attached pictures of the filters to see if that's the kind of dirty filter that can contribute to my
engine running problem.
I will check the other items you mentioned and let you know.

 

[frank.dimambro]

View attachment 21442View attachment 21443

I took the small filters out of each card and while there is some dirt the Magneto Carb filter it's not
completely clogged. The PTO carb filter is a lot more dirty.

I've attached pictures of the filters to see if that's the kind of dirty filter that can contribute to my
engine running problem.
I will check the other items you mentioned and let you know.

I took the boat out today with the new set of carbs, and and Clean filters.
I also run a Car electric powered fuel pump + filter in place of the carbs
to clean the fuel lines and tank of any more residue that was has the
potential clogging up the filters. I ran that for a day then reconnected
the fuel lines to the carbs.
I finally took it out today and it worked perfectly, I was able to go a the
lake speed limit of 30MPH while towing my wife and kids (one at a time)
on a towable.
We had a great time thanks to all your help.

 

[kilgorekb]

Lake speed limit? Oh, California :facepalm: