I bought a 14ft lund with a 1996 30hp mariner 30 that has oil injection and I cannot get it to run well.
It was accelerating very slowly. It would eventually reach a plane, but it took a long time to get there, this engine should have snappy throttle response, but when I put the throttle down it just bogs, then slowly accelerates.
While taking the carburetor apart for the 3rd time I noticed that it had an 066 main jet, which is for the 40hp; I thought "hey that's the issue," so I ordered the 054 jet for a 30hp. Now it runs worse, it won't run over part throttle without stalling. If I go wide open and hold the key (enrichment circuit) it would run properly for a second, then bog, so it appears to be a lean condition.
The engine idles and starts well, though.
Things i've done:
- cleaned the carb and installed the correct jet.
- checked the compression: 135psi both cylinders.
- Checked the spark, strong on both cylinders.
- timing is 3 degrees at idle and 25 degrees over 3000 rpm, which is exactly to spec.
- The fuel pump gives a nice squirt of fuel when cranking the engine.
- The oil injection seems to work fine, the carb bowl is always full of blue fuel.
- Squeezing the primer doesn't change how the engine runs which helps reiterate that the fuel pump works and the needle in the carb isn't leaky.
- checked the reeds, see below.
I finally ripped the reed box off the front of the engine even though the problem is almost never reeds. One cylinder has the reed valves closed all the way touching the plate. The other cylinder has a few reeds with some play, I can't find the specification for how much play is acceptable, it doesn't seem too excessive (maybe 5 thou).
Anyway, I am having my butt kicked on this one, any help appreciated.
It was accelerating very slowly. It would eventually reach a plane, but it took a long time to get there, this engine should have snappy throttle response, but when I put the throttle down it just bogs, then slowly accelerates.
While taking the carburetor apart for the 3rd time I noticed that it had an 066 main jet, which is for the 40hp; I thought "hey that's the issue," so I ordered the 054 jet for a 30hp. Now it runs worse, it won't run over part throttle without stalling. If I go wide open and hold the key (enrichment circuit) it would run properly for a second, then bog, so it appears to be a lean condition.
The engine idles and starts well, though.
Things i've done:
- cleaned the carb and installed the correct jet.
- checked the compression: 135psi both cylinders.
- Checked the spark, strong on both cylinders.
- timing is 3 degrees at idle and 25 degrees over 3000 rpm, which is exactly to spec.
- The fuel pump gives a nice squirt of fuel when cranking the engine.
- The oil injection seems to work fine, the carb bowl is always full of blue fuel.
- Squeezing the primer doesn't change how the engine runs which helps reiterate that the fuel pump works and the needle in the carb isn't leaky.
- checked the reeds, see below.
I finally ripped the reed box off the front of the engine even though the problem is almost never reeds. One cylinder has the reed valves closed all the way touching the plate. The other cylinder has a few reeds with some play, I can't find the specification for how much play is acceptable, it doesn't seem too excessive (maybe 5 thou).
Anyway, I am having my butt kicked on this one, any help appreciated.