1999 250EFI loses rpm

fishfast

Recruit
Joined
Aug 4, 2010
Messages
2
Howdy!

I'm a long way from a service center, currently 20 miles off the coast of Belize, so I either fix this or fly in a mechanic. I'm really hoping you guys can give me some clues. Port engine suddenly loses rpm. Sometimes it revs right back up. Sometimes is dies. When it dies, it always restarts. This happens randomly and I can't cause it on purpose. Checked fuel issues and didn't find any problem there (strbd engine does not have this problem). My only clue is that this seems to happen most often in rough water at rpm of about 3800 and up, when the boat is pounding. Like something electrical, bumps loose, engine nearly dies (or does die), and then bumps back to life on the next few waves. Typical runs are 1-2 hours and it may do it 3-4 times or not at all. If you catch the rpm loss in time, you can sometimes throttle back to about 1500, wait a second, and then throttle right back up.

Up till now, this has been a nuisance but now, port engine won't start. Checked fuses and checked and cleaned every electrical connection in the engine I can find. No corrosion on any of it. While going through the connections and trying to get it started, there were times when it would and would not tilt, would and would not fire, would and would not turn over (no starter engagement). It's like there are suddenly multiple electrical issues but that just doesn't seem to make sense either.

I'm really stuck. Any body have any ideas?

THANKS!
 

jerryjerry05

Supreme Mariner
Joined
May 7, 2008
Messages
18,196
Re: 1999 250EFI loses rpm

Sounds like a fuel issue.Do a pressure test on the schrader valve.What ser#? The pressure varies on different motors.You have 2 pumps.Make sure the diaphram on the mechanical is ok.Water in your fuel filter?
Drain the vapor sep.for water/dirt.
Don't know if they put ethanol in your fuel but it's messing up a lot of stuff.

Ethanol is messing up a lot of motors.It's delaminating the inside of older hoses causing clogs in the carbs/injectors and fuel filter.Check for soft hoses and junk in the filter on the motor.Check the diaphram J
 

fishfast

Recruit
Joined
Aug 4, 2010
Messages
2
Re: 1999 250EFI loses rpm

Thanks Jerry. Everything down there is E85 from Mexico or Venezuela. I upgraded hoses before I sent the boat down 6 months ago. I replaced the bulbs a couple of months ago. They were pretty old and turned real soft after the ethanol hit them.

I'll follow your suggestion on the fuel. That still leaves me with the electrical issues.

Thanks!
 
Top