Logo
FULL SITE MENU

Ti ing issue: WOT crank timing vs engine run timing, merc 60Hp 3 cyl

J

JohannesDeVr

New member
Hi, I bought a merc 60Hp 3 cyl 2 stroke, but cant get it to exceed 3000RPM under load. When in neutral I can get it to 4800 RPM. It should be able to do 5200 RPM.
Carbs has been cleaned,
Fuel lines cleaned
Fuel pump redone.
New spark plugs

When checking tbe crank idle and crank WOT timing this was according to soec 2 degree after and 24 degree BTDC. When running the motor at 3000 RPM in neutral I notice the timing to be 12-14 degrees BTDC. What would be tbe cause and how could this be rectified?
 
Hi Johannes,

There is a Youtube clip that explains this. Its possibly when you push the throttle forward it there are two levers which seem to adjust the timing. When you in neutral there is no load and hence you dont push it as far forward to achieve the revs.

Regarsd
Leachy
 
Sounds like it might be running on 2 of 3 cylinders.-----Post your compression numbers.---And does spark jump a gap of 3/8" ( 1 cm ) on each lead ?----Do not wind it up in neutral as that is not good for the motor.----And it will rev up running on 2 of 3 cylinders.
 
Compression is more than 9 bar on each cylinder. Spark seem te be strong on each plug. I did check the difference in running with no 1 and then no 2 and then no 3 spark plug removed. It seems they are all contributing well to the performance
 
leachy said:
Hi Johannes,

There is a Youtube clip that explains this. Its possibly when you push the throttle forward it there are two levers which seem to adjust the timing. When you in neutral there is no load and hence you dont push it as far forward to achieve the revs.

Regarsd
Leachy
Click to expand...
Thanks Leachy, what did you used in the search bar to find this video? I did lots if searches without success
 
Back
Top