Logo
FULL SITE MENU

97 25hp fuel or timing issue

J

Jamesaelliott

New member
97 25hp c25MLHV. having problems with bogging at high rpm’s in gear. Runs flawlessly and starts first pull on idle. Replaced fuel tank, ethanol free gas, primer, bypassed fuel connection at motor, filter, and pump. Cleaned the carb about 20 times. Have also checked reeds. Spark test is great even while WOT during bogging, compression is 125. Prop shaft is clean. I’m about ready to light a match to it. Unless by chance I’ve managed to miss clean the carb 20 times. “Had every jet, air, and removable screw/part off and cleaned” haven’t tried soaking it yet. Only thing that’s left is timing. So would anyone happen to have a pdf repair manual or by just knowledge on how I can check the timing without a light? The timing marks and cylinders line up tdc where they’re supposed to be. I just don’t know what to look for in the advancing timing while throttling up. All the linkages seem to be working.
 
Hope someone answers i have the same issue with a 20hp 1991. Runs great but at 1/2 throttle it bogs. I have done everything but no success. My timing is 5 at idle and 20 at wide open using a gun.
 
When the motor starts to bog down mist some gasoline into the air intake system. If it picks up and runs that is an indication that something is amiss in the fuel supply system.

Many times it is best to clean a carburetor in a heated ultrasonic cleaner.
 
boscoe said:
When the motor starts to bog down mist some gasoline into the air intake system. If it picks up and runs that is an indication that something is amiss in the fuel supply system.

Many times it is best to clean a carburetor in a heated ultrasonic cleaner.
Click to expand...
during bog if I spray gas in the carb it immediately dies! I believe I’m getting too much fuel, I just installed a carb kit and have the air/fuel set to 1-3/8 as stated in service manual
 
Not to jump on board we have rebuilt our 20 hp getting 130 and 140 compression. Carb rebuilt. Tan spark plugs after running for 20+ minutes. Out of gear it revs great. Put it into gear runs great till you get 3/4 throttle then it starts to run rough and will dies. Timing is set to spec also. Now we did test it still.on the trailer but think that would not cause that but who knows. Also notice a ground wire that connects the case to the lower unit broke but also unsure it that would. Cause.the issue. Thinking maybe CDI? Any help please.
 
Possibly. Still haven’t fixed mine. I got the repair manual for mine. I doubt it’s the same specs but use an analog tester to test cdi I’ll attempt to post a picture of my required specs
 

Attachments

  • IMG_5317.png
    IMG_5317.png
    831.1 KB · Views: 38
Hi.prettty sure the 20.and 25 are almost the same motor parts seem.to be the same most of the time. It is a weird problem.
 
Yes it is, sucks because duck season is around the corner and haven’t found my issue lol. Haven’t gotten the chance to test my cdi box though.
 
Beginning to.think it is maybe a stater or mag issue just unsure how to test that. Seeing it works great in idle even at max throttle that it allows.
 
Back
Top