Average RPM at Idle

[Captin_Kirk]

I have finally got my p60 running. It idles in neutral around 1900 to 2000 rpms That seems really fast to me. What is the average that it should be?

[motion30]

700rpm

[GordMay]

Most diesels idle between 650-850 RPM.
I’d think 1900 RPM is beyond high idle for any engine.

[chala]

Perkins 2 cyl. Have a min. idle speed of 1200 rpm, 3 cyl. 800 rpm with automatic fast idle up to 1200 during warm up. 1900 rpm is a fair spin, make sure the rev counter is properly set up.

[fishwife]

I think the P60 in question is a petrol engine, but I'm often wrong .

P.

[GordMay]

Originally Posted by fishwife

I think the P60 in question is a petrol engine, but I'm often wrong.

Not this time.
A similar (?) 'Atomic 4' gasoline engine runs (& shifts) at an idling speed of 600 to 1000 rpm.

[Captin_Kirk]

Yes it is a gas motor. I am assuming though that it is about the same. around 700?

[Jim Cate]

G'Day Cap'n,

Yep, that's way too high. won't hurt the engine, but will make slow speed manuvering terrible!

So, what's wrong? First, check the linkage to be sure that it allows the throttle to return to the stop screw on the carburator. If it does, try turning the screw to reduce the throttle setting. If that doesn't fix it, then it is likely an air leak, perhaps under the carb where it meets the intake manifold. A new gasket or perhaps just tightening the mounting bolts might then fix the situation... but somewhere some extra air is getting in and making the engine think that the throttles are cracked open a bit.
Shouldn't be too hard to track down.

Good luck

Jim

[Captin_Kirk]

It is at about 1/4 throttle. If I slow it down it stalls. Would that be an air leak, or not enough fuel?

[Jim Cate]

Originally Posted by Captin_Kirk

It is at about 1/4 throttle. If I slow it down it stalls. Would that be an air leak, or not enough fuel?

G'Day again, Cap'n,

First guess is a badly maladjusted idle needle valve, or more likely, a clogged idle passage in the carb body. Disassembly of the carb, soaking in carb cleaner and then carefully blowing out all the little passages in the carb just might solve this one. Typically, the needle valve should be set around 3/4 to 1 1/4 turn off its seat.

Cheers,
Jim

[Captin_Kirk]

Yes, I just did all that before I started it. It used to only run at half choke. Now it runs with the choke off, but very fast. I followed the instructions in the rebuild kit, but I will verify again.. When it was apart I did notice that the idle jet was kinda beaten up. Looks like the head was broken apart when the PO tried to remove it. I was unable to get it out for fear of breaking it. I could blow air through it though.

[Ex-Calif]

Check for intake manifold leaks downstream of the carb.

Use a can of carb cleaner with a nozzle - spray near jointed flanges and listen for rpm changes.

Check both carb to manifold and manifold to head.