2002 125 ELPTO RPM Liimiter????

Tim Wagner

Petty Officer 1st Class
Joined
Sep 7, 2003
Messages
201
My motor seems to be phasing back at 5200 RPM's all on its own.
Cant fiigure out why the heck its doing it.
Could there be some kind of automatic limiter thats cutting back my RPM's to 4600-4700 thats malfunctioning?
If so, is there a way I can bypass/disconnect it to eliminate it from being the problem?
Ive been up one side and down the other of that motor and every thing checks CORRECT.
The motor is great out of the hole but 1-3 seconds after it hits top RPM at WOT, it backs off like you backed off on the gas.
 

schematic

Lieutenant Junior Grade
Joined
Jan 12, 2008
Messages
1,102
Re: 2002 125 ELPTO RPM Liimiter????

sounds like you are losing a cylinder. don't run it like this for long until you repair, as it may be fuel related and take out a piston. start with the basics. assist with primer bulb when failing, plugs, spark test with timing light when under way on each cylinder, clean carbs
 

Tim Wagner

Petty Officer 1st Class
Joined
Sep 7, 2003
Messages
201
Re: 2002 125 ELPTO RPM Liimiter????

fuel filter is new. carbs are cleaned, linked and synced, fuel pump is rebuilt, primer bulb squeezed at WOT doesnt make a difference, various hose chunks replaced, ran on seperate tank. doesnt make a difference.
 

schematic

Lieutenant Junior Grade
Joined
Jan 12, 2008
Messages
1,102
Re: 2002 125 ELPTO RPM Liimiter????

You haven't eliminated ignition yet. Use a timing light as an indicator, one cyl. at a time when its bogging
Wouldn't hurt to check coil and wire resistance (easy to do). It may show up a problem saving you the timing light test
 

10bender24

Recruit
Joined
Jun 30, 2013
Messages
3
Re: 2002 125 ELPTO RPM Liimiter????

My 2005 Merc 125 is doing the same thing, runs great at idle and up to 4600 rpm then it starts cutting out.. Did you figure yours out yet.. Thanks..
 
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