Rough Running 99 Moomba Outback

Moomba99

Cadet
Joined
Jun 18, 2020
Messages
6
Boat recently started to lose power at 36 mph and has had trouble maintaining speed after 34 mph. My driver said it was surging a bit especially in the corners.

I do a one mile up the lake at 36 and then a left hand keyhole turn and come right back down the same path. He said it was struggling to maintain speed and then surged in speed on the turn. I ski a lot, and one of my buddies on shore who also drives for me said the boat sounded different coming down the lake.

I checked the carb filters, the fuel pump flow, the fuel water separator, sprayed carb cleaner around the gaskets for air leaks, checked the plugs, distributor and cap look fine, advanced and retarded the timing, (runs a little better retarded) checked the strainer and impeller for cold circulation, also checked water pick up. Warm water is flowing out of exhaust, both sides. idle is a bit rough and it just sounds off. Going down the lake it usually sounds smooth and jumps from 36 to 40 very quickly. When I tried it today after all that checking it did not respond well. Am I missing something?
 

seafan2824

Cadet
Joined
Jun 10, 2020
Messages
14
Have you checked the fuel lines from the tank to the fuel pump? I've got an 88 Citation 4.3 Merc and I'm having similar issues. I can let you know more on Sunday... I'm replacing fuel lines from tank to fuel pump. If you don't remember last time you replaced them, that's where I'd start. Fuel lines break down from the inside out, and once they breakdown they will start to block the fuel flow. On my 88, I can get up to about 25 MPH no problem, anything after that the boat is not having it. My guess is you have part of that broke down fuel line plugging up your line to your pump, hense no fuel, hense the sputtering, speed jump, etc. If your other visual inspections look good I'd start there. Should be an easy enough job.
 

Moomba99

Cadet
Joined
Jun 18, 2020
Messages
6
Just checked the fuel line from the pump to the tank. Blew air into the tank and it was a good flow after the fuel reached the tank. I did check the carb filters and fuel pump flow into a jar. All good. Also I just pulled the thermostat housing and it is pumping through there at a good pace.
 

Moomba99

Cadet
Joined
Jun 18, 2020
Messages
6
Just took it out for a ski run at 34 mph. On the turn the boat surged and accelerated. It had done this a few times before when the boat was running well just prior to these issues. Does that mean the floats are off or stuck somehow?
 

Moomba99

Cadet
Joined
Jun 18, 2020
Messages
6
Could this be a distributor issue? I can get new lines, cap rotor and distributor rather quickly.
 

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
70,468
Ayuh,..... The Delco Voyager is the "Go to" marine ignition system,......

Installation is pretty basic motor repair,.....
 

Moomba99

Cadet
Joined
Jun 18, 2020
Messages
6
Will check that out. Thanks. Is it set up for right hand or left hand rotation? My block is 350 Chevy 5.7 Indmar.
 
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