MD7a:Lacking power/low RPMs

[Brian]

My MD7A won't turn up more than 2,000 RPMs. We used to get at least 2,300. While we historically have cruised around 2,000 it is nice to have that extra power.

Here is what I have ruled out:

1. Getting plenty of fuel-just replaced both the primary and secordary filters

2. Throttle is fully opening

I had the valves done last year and this is when I noticed the drop in power. I checked the clearances last year, but will be checking again tonight. Could this be an exhaust problem? I did clean out the manifold at the same time.

It does not burn any oil. So I don't feel it's a compression problem.

Bad injector(s)?

Any suggestions would be appreciated.



Brian@harvardthermal.com

[John R.]

Getting enough air flow? How's the prop condition? Trans okay? Any smoke? Correctly adjusted linkage?

My MD7A won't turn up more than 2,000 RPMs. We used to get at least 2,300. While we historically have cruised around 2,000 it is nice to have that extra power.

Here is what I have ruled out:

1. Getting plenty of fuel-just replaced both the primary and secordary filters

2. Throttle is fully opening

I had the valves done last year and this is when I noticed the drop in power. I checked the clearances last year, but will be checking again tonight. Could this be an exhaust problem? I did clean out the manifold at the same time.

It does not burn any oil. So I don't feel it's a compression problem.

Bad injector(s)?

Any suggestions would be appreciated.

[Larry DeMers]

The clue may be the valve job that you had done just before the problem started. I bet the valve timing is wrong..or slightly off. By advancing or retarding the timing, I have helped or hurt starting efforts during in the cold for instance, so I bet that it also would have an effect on top rpm at a given fuel rack position.
Good Luck

Larry DeMers
s/v DeLaMer
CD30 Lake Superior

My MD7A won't turn up more than 2,000 RPMs. We used to get at least 2,300. While we historically have cruised around 2,000 it is nice to have that extra power.

Here is what I have ruled out:

1. Getting plenty of fuel-just replaced both the primary and secordary filters

2. Throttle is fully opening

I had the valves done last year and this is when I noticed the drop in power. I checked the clearances last year, but will be checking again tonight. Could this be an exhaust problem? I did clean out the manifold at the same time.

It does not burn any oil. So I don't feel it's a compression problem.

Bad injector(s)?

Any suggestions would be appreciated.

demers@sgi.com