Perkins P6 Over Reving

R W · Post by **R W** » Thu Apr 30, 2009 10:06 am

Have a recently reassembled P6 which even with the
throttle fully closed appears to be reving out to around its working
speed.
Revs can only be reduced by restricting the air intake
or by use of the shut off control.
A new diaphram has been fitted, the housing, pipe & fittings, throttle operation have all checked out OK.
Any advice regarding this problem would be greatly appreciated.

Aussie Frank · Post by **Aussie Frank** » Thu Apr 30, 2009 11:36 am

Hi RW,
Although I own a P6 I am no expert, but you say recently assembled. Have you fitted the air filter yet? I know from other posts here that vacuum governed Fordsons rev real hard when the air cleaner is disconnected. The restriction in the filter is what helps the govenor work as I understand it. The other thing I would look for is an intake manifold air leak.

Also when the new diaphram was fitted did you check the fuel control rack to make sure that it was free to move. There is quite a lot of information on the old site regarding stuck racks in E1A Majors and how to fix over reving. Not the same engine but some of the tips might be useful. There are links at the top of the page showing how to search. Just go to the Sticky: Looking for information? Here's how to find it!

Just a couple of ideas I had that might work up until a real expert comes up and says ah I know what that is, you forgot to tighten the screw on the whatsathingy. Good luck with it and keep us posted.

Regards, Frank.

Grani · Post by **Grani** » Thu Apr 30, 2009 11:56 am

I am no expert on P6 but if it has two vacumtubes from the diaphram to the inletmanifold then perhaps you have switched them by misstake.

R W · Post by **R W** » Thu Apr 30, 2009 12:32 pm

Thanks for your replies.
Re Air Cleaner; The oil bath is connected the pre cleaner
is not.
Re Connecting Pipes; Only one pipe going from the
intake manifold to the governor housing.

R W · Post by **R W** » Tue May 05, 2009 9:43 am

The problem has been overcome, the throttle adjustment was to wide.
I had not altered this as it was idling OK before the engine was pulled down and the adjustment had been left as it was.

Aussie Frank · Post by **Aussie Frank** » Wed May 06, 2009 7:47 am

Hi RW,

That is great news. It is usually the simple things that trip us up. Just goes to show how tired the old girl must have been before the rebuild. Thanks for letting us know what the problem was.

Regards, Frank.