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Farm Pumper, or not Pumper

muzzery

Registered
Hi all. I’m having a crack at starting this old girl. Still nothing. The only thing pumping is my heart huff puff! It will fire if I close the valve gap, practically advancing the exhaust valve timing, so you can see it flaming out the exhaust. It makes me wonder if there is too much compression, for the old school spark plug? I did have it resleeved and there’s pretty good compression when you turn her over. I can’t see what else could be wrong. It has run once for about 15 seconds so I reckon timing is right.( spark mark on flywheel is showing correct position)
 

Rusty Engines

eMail NOT Working
Re: Farm pumper . Or not pumper.

flaming out the exhaust???
Is the exhaust port at the bottom of the stroke not blocked as that is the main exhaust outlet

Ian
 

muzzery

Registered
Re: Farm pumper . Or not pumper.

No, it’s functional. The flame out happens at the start of power stroke- if the valve is advanced to open early. Back the valve timing off to normal, and nothing fires at all.
 

Scotty 2

Registered
Re: Farm pumper . Or not pumper.

Hello Muzz
Back to the beginning and check everything from governor operation/setting to timing and everything in the middle. I did have trouble with a pumper because the governor was set too light. It was wanting to miss with the cranking speed.

Cheers Scott
 

cobbadog

Registered
Re: Farm pumper . Or not pumper.

Back to the basic s for sure. These can be fun to get right but once running right they go for ever, As Scotty suggested try increasing the governor to make it run faster so that more fuel is getting in or pour a bit of fuel down the plug hole to see what happens.
Ignition timing is important so check it again and leave your valve clearance open as they are not normally that close.
Check for a good spark and that the plug is firing or use a known good plug to eliminate a dodgy plug.
Mine was one of those engines that wouls start only when it wanted to. You could start it a 100 times at home hot or cold and take it out and it would not fire. Turned out the magneto needed charging up and now it starts anytime and anywhere.
Persist, you will win.
 

eddie bedwell

Registered
Re: Farm pumper . Or not pumper.

Hi Team,
link is to the F & J farm pumper operators book
http://oldengine.org/members/allen/Manuals/FJpumpengine.pdf

Page 11 tells where the exhaust valve should open and close at.

If your suspect spark plug or the magneto power is at fault, in my experience if the magneto fires each time the piston comes near TDC a faulty plug or weak magneto will fire the residual mixture on the off (non compression) stroke and give results such as you are seeing--if the engine had a timed mechanical inlet valve it would tend to backfire out of the inlet/carby.

With an atmospheric or automatic inlet vale it would not fire out the inlet as the pressure rise from firing would help keep the inlet valve closed and so would backfire out the exhaust, especially if you have closed up the valve clearance so that the
exhaust valve would tend to be open after TDC.

Generally with older engines the valve clearance is adjusted to get the valve opening and closing positions correct for best running.

The faulty spark plug can fire under less compression, as you have said--you may get some success if you closed the plug gap down to say around 0.010" to 0.014" and see what happens as this tends to lessen the load on a tired maggie and sad plug.

A weak sparking magneto can be fooled into starting an engine if you rub a soft black lead pencil carbon onto the plug electrode gap--you will get one or two sparkly sparks that can fire the engine off and get enough speed up for the maggie to continue firing the plug--works most times in my experience--your mileage may vary.
Cheers,
Eddie B.
 

muzzery

Registered
Okay👍 There’s some good advice here, thanks gentlemen! I had wondered about the spark gap. It’s much bigger at the moment so I’ll try that. The maggy is a fully reconditioned one from a bloke out back of Toowoomba. I trust he did the right thing by me, it was rather expensive, but perhaps it could use fettling.
Thanks, Murray
 

Tim B

Subscriber
Last Subscription Date
05/06/2019
Turn the flywheel the other direction. Yeah, I guess that wouldnt help. Just looks like cam and and/or ignition timing is way off.
 
Last edited:

Scotty 2

Registered
Just uploaded video you tube so you can see it wearing me out��
Hire it out to the local gym. People pay a fortune for that kind of workout.

Yep. Check all the timings again.

Another question....just how high in the air is your pumper? It looks as though a bloke is near walking under it. Or is he just my height ie short @rse.

I notice it's the Wico version. I found with ours that a simple tilt of the magneto within the range of the mounting bolts will upset things. Check the timing with a timing light.

Cheers Scott
PS: just to peeve you :O :D
https://youtu.be/UkxyotNh6rQ
 

eddie bedwell

Registered
Hi Murray,
unless the video is giving an incorrect impression there does not seem to be a good snap open of the Wico mag.
Most of these are opened by loading a drive spring which overcomes the magnetic attraction of the magnets and the points carrier/armature, opening them with a good fast snap giving a good healthy spark.

Have had nothing to do with these pumper engines but my Cooper/Stover Wico powered engine has a drive spring that if they are weak will cause a weak spark.
As Scotty points out a simple magneto angle adjustment within the range of mounting bolt hole clearances can make a difference as to how these Mags work.

If the guide dowel for the points carrier/armature or its guide bore are worn or the alignment needs a tweak the carrier/armature can separate from the magnet one side before the other and cause a weak spark.
Each side of the carrier/armature has to separate together equally for best results--not sure if my terminology is correct for the magneto parts.

The engine also seems to be firing on the exhaust stroke which would cause the flames from the exhaust as we appear to see.

You could check your valve timing by checking that the exhaust valve opens at or just before Bottom Dead Centre and closes at Top Dead Centre, you may need to move the cam gear teeth timing to the crank gear to get as close as possible to this with emphasis on exhaust closing at TDC.
You may need to adjust the valve clearance to get these timing points correct--it is often normal on older engines to adjust the valve lash to get the timing correct--not unusual to see 1/4" or more clearance with no harm to the engine.

Some N Type Ronaldson Tippets, among many other engines, have their tappets adjusted like this to get the valve timings correct.
The valves are not adjusted to a set clearance but are adjusted so the timing is correct--seems weird but is how some makers designed their engines.
Not saying this is how a pumper engine is but I mention it so you are aware, if it is so.

Hopefully others with these can correct me if needed.
Cheers,
Eddie B.
 

muzzery

Registered
Thanks everyone, we have a winner! I’ve posted a new thread with a short video of first startup. Couldn’t have done this without the massive help of the people on this forum!
 
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