indmar 350 woes

I have a 2001 launch ssv with with the tbi indmar 350. The boat runs great at idle, pulls out of the hole great, sounds great at 4500 rpms even. But when pulling a wakeboarder (22-25 mph) it will cruise along fine for a while(like 10 min to even a half hour) then just die down and if i try to throttle it will back fire. (seems like timing is off but just strange that its not always off) so when it dies down it will come to idle, and idle perfectly. if i try to take off right away again there is no power and it will backfire, but if i wait a minute or two it will pull out no problem and go for a nother 10 minutes to even a half hour. It also sounds like its missing sometimes at wakeboard speed. If anyone has any insight into this or has ever had a similar experience i would really appreciate the input, thanks

It could be going into limp mode - however the backfire is unusual. Most common cause of limp mode is water temp or flow on newer boats.

Also similar to a distributor cap / rotor problem I had before. Inspect the cap and rotor for corrosion.

hmm, so if my impellor was bad would that cause this limp mode? because I have been noticing more exhaust smoke though my temp is still good

and the back fire is only if you try to throttle it down, otherwise it won't backfire

I've been hearing issues on these engines due to the higher ethanol content in a lot of gas. It's probably not a great solution but how about giving a tank full of non-oxy fuel a try?

Your issues sound more fuel related. I would be looking at a clogged fuel filter or faulty fuel pump....

I changed the filter, could be pump but seems to intermitent to me

What kind of motor? Possible vacuum leak? I just had that issue in my truck (GM 5.3L vortec). Intake manifold leak, and it acted very similar to a fuel pump aswell as the backfiring.

5.7. its tbi so no intake manifold persay, but i guess it could be the thottle body gasket