Car dropped 250 RPM and is now stuttering
I reved it up and then blocked it off a few times. No change.
I sprayed for a vacuum leak, nothing.
I opened the valve covers, no bent anything.
I did notice the oil sitting on the top of the rockers looked weird. It looks like oil that you get when you break in a cam. Which is what I did about 100 miles ago. I broke the cam in and then changed the oil. I'm guessing what I am seeing is residual from that cam break in. You can see the "cloud" in the picture below.
At this point here is exactly what it is doing.
Idles at 400, the carb idle is set to 750.
While idleing if you close off the butterfly it increases the revs.
When you release the butterfly's back the idle drops down and the engine dies.
It revs healthily. It is not missing a piston.
It revs its self up when a little gas is provided. Example would be taking it from idle to 750 rpm it will actually over rev up to 1250 once it grabs some gas and air.
When at higher rpms it will bounce up and down. Example, hold throttle at 2000 and it will bounce up to 2500 and back down on its own.
The gas is good.
It starts reliably.
My next step is to take the carb off and open it up looking for junk. Last time I opened it up it was very clean inside. The gas tank is new. There is now sign of crap in the fuel filter.
I'm going to change out the carb plate and spacer gaskets when it take it off.
I reved it up and then blocked it off a few times. No change.
I sprayed for a vacuum leak, nothing.
I opened the valve covers, no bent anything.
I did notice the oil sitting on the top of the rockers looked weird. It looks like oil that you get when you break in a cam. Which is what I did about 100 miles ago. I broke the cam in and then changed the oil. I'm guessing what I am seeing is residual from that cam break in. You can see the "cloud" in the picture below.
At this point here is exactly what it is doing.
Idles at 400, the carb idle is set to 750.
While idleing if you close off the butterfly it increases the revs.
When you release the butterfly's back the idle drops down and the engine dies.
It revs healthily. It is not missing a piston.
It revs its self up when a little gas is provided. Example would be taking it from idle to 750 rpm it will actually over rev up to 1250 once it grabs some gas and air.
When at higher rpms it will bounce up and down. Example, hold throttle at 2000 and it will bounce up to 2500 and back down on its own.
The gas is good.
It starts reliably.
My next step is to take the carb off and open it up looking for junk. Last time I opened it up it was very clean inside. The gas tank is new. There is now sign of crap in the fuel filter.
I'm going to change out the carb plate and spacer gaskets when it take it off.
