# Injector pump problems



## Jw2622 (Dec 7, 2014)

I had fuel leaking into oil so I struggeled to remove the pump and replace the seal after getting everything back together when I cranked the tractor it was ideling very fast. I reajusted the linkage and when it backed down to idel it just keeps slowing till it shutoff. Now the tractor doesn't idel, I have to use the foot throttle to keep it running.
Any help would be greatly appreciated.
The tractor is a mid 80s 340A with a CAV pump


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## sixbales (May 18, 2011)

Howdy Jw2622,

Attached is a copy of a CAV pump instruction book. I've sent your post to a friend of mine who is an expert on injection pumps. Please do not do anything to the pump till I get his response. I suspect that you screwed up something putting it back together. That's no big deal, he'll tell you what to do.


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## Jw2622 (Dec 7, 2014)

Thanks I'll wait for his reply


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## sixbales (May 18, 2011)

Jw2622,

Attached is the response from the injection pump expert. 

*"Depending on what pump # he has, its possible he knocked a flyweight out of place.. 

It just depends on if he had to remove the center screw from the drive hub OR if he had to remove a c-clip from the drive shaft..

OR when he hooked up the inlet and outlet lines from the filter head, he got them crossed..

AND

Its possible he just has air in the system and it rev'ed up before it died and now he adjusted the idle to low...

Another thing is.. did he change the filter while the pump was off?? he might have put the gasket on in the wrong place.. on the filter instead of up in the housing.." *

Hope this helps.


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## sixbales (May 18, 2011)

I think that I would treat it like you still have some air in the system somewhere. Bleed the filter by opening the bleeder screw on top. Open the bleeder screw on the pump and crank the engine till you are satisfied there is no air at that point. Then crack open the connections at the injectors and crank/bleed.

Set the idle linkage back to where it was originally??


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## Jw2622 (Dec 7, 2014)

I'm thinking it may be a flyweight. 
Let me describe what's going on a little better. First the tractor is in Va. at father in-law I'm in Va. When I removed the pump I dis thak the bolt out from center shaft. I did not take any part of the pump apart or mess with the filter. When I replaced the pump removed the plug on the side of the pump to allow it to fill with fuel then bled at the injectors until it cranked. At that point it was running very fast I pulled the kill, thought it was running away. Cranked again and had the same results. That's when I thought I could adjust the linkage to slow it down. Once it drops below about half throttle it will continue to slow until it shuts off. It runs ok but it's all or nothing. A guy told me something was going on under the cap. I didn't realy understand but thought I'd take a look anyway. Everything looked ok to me being I didn't know what I was looking at except the spring looked to be stretched. I had another one in an old pump so on my next trip to visit I replaced the spring, careful to use the same holes. Cranked the damn thing, again running fast. Took the top off dropped one hole and was back to where it was before replacing the spring.
When I got this tractor the head was off and it came with a rebuilt head still wrapped in plastic along with new or rebuilt injectors. I pulled the engine and had it completely rebuilt. My paw in-law had an old 8n I thought this 340a with a loader would suit him better. It has about 40hrs on it now. Sure would like to get it running right again
Your help is appreciated!


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## Jw2622 (Dec 7, 2014)

Ment to say I'm in Ga.


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## sixbales (May 18, 2011)

I sent your second note to my friend/injection pump expert. Here is what he said:

*"One more thing to check BEFORE condemning the pump..

When he took the center screw out.. did he take it COMPLETLY out of the hub.?? or loosened it enough to pull the hub and left the screw in the hub..??

I ask because the screw has 2 washers on it.. and if you get them out of place or cocked it will do as described..

ALSO, what did he tighten the screw to.. its supposed to be tightened to 30ftlbs, 3x ...tightened, loosened, tightened, loosened and again 1 more time.. with blue Loctite...

IF the screw is loose or the washers are cocked, the engine will rev...

He might be able to tell by removing the pump again and checking the hub endplay... it should be no more than .011",,

If he pulls on it and it goes "clunk, clunk" then its the washers or screw..

On the other hand.. if its the flyweights, he cant fix it.. has to be sent off.. the flyweights and drive shaft are the 1st things to go into the housing..and the pump has to come completely apart to fix.."*


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## Jw2622 (Dec 7, 2014)

Thanks for your help. My next trip to Va I'll pull the pump and check.


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## sixbales (May 18, 2011)

Attached is a parts diagram for your injection pump. Items #41 and #42 appear to be the washers referred to above.


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