Suffolk Punch running issue on Qualcast Cultimatic.

[jonnym 9]

Hello all.

 

I've recently bought a Qualcast Cultimatic with an alloy Suffolk 98 engine and Zenith carb (which I think makes it an old one) from ebay.

 

It was bought as a non runner, but on the plus side it was local.  I put £60 as my highest bid and won it for £12.50!

 

I cleaned out the tank, removed stripped and cleaned the carb, stuck in a new plug with a dash of easy start, fresh oil, and tÄ¥en a dash of easy start in the air intake and it started third pull. 

 

The problem I'm having is the throttle doesn't seem to have any effect, I have to set it on the choke.  The carb and throttle spring seem to be setup correctly. 

 

The only part of the carb which didn't get cleaned was the long jet as I couldn't remove it with out damaging it. Number 21 in the PDF below.

 

The other worry is the bracket where the spring attaches has been brazed, I'm slightly worried they have done this insitu which has fried the butterfly inside.

 

What do you think?

 

thanks

 

Jon

Zenith carb0001.pdf

[C-101plowerpower 548]

I think someone put Suffolk bits on a briggs

[sten 84]

The jet 21 is usually the one that is blocked, I remove the jet by putting the point of a dart in the hole to stop it distorting then give it some gentle heat making sure there is no petrol left in bowl, then use a pair of pin nose pliers to gently twist and pull the jet out but proceed with care, the jet is easily damaged.

[jonnym 9]

Nice idea using a dart.  I might have to find a nail as I don't have a dart.

 

I haven't notices any Briggs and Stratton bits on there, which bit do you mean?

 

thanks

 

Jon

[sten 84]

Nice idea using a dart.  I might have to find a nail as I don't have a dart.

 

I haven't notices any Briggs and Stratton bits on there, which bit do you mean?

 

thanks

 

Jon

The point of a nail is usually square, if you can find a nail the right diameter to fit right in it should be ok.

[jonnym 9]

I have a good range of small drill bits in many increments, which is probably a better bet. 

 

I was going to buy a new jet and remove the existing one buy tapping it to allow a bolt to be used with a little heat.   

 

Your trick will save me alot of time!

 

Thanks again

jon

[C-101plowerpower 548]

i mean this:

 

2horse briggs

 

same 2hp briggs with a suffolk cowl

[jonnym 9]

OK I see what your saying.

 

They did a Cultimatic Super with a Suffolk 98, a Cultimatic Special with a briggs and stratton 3hp and a Cultimatic deluxe with a 4hp Briggs and Stratton.

 

I think (although I'm not sure) I have seen a plate on it saying Suffolk.   That said if it got another 1hp that's fine with me!

 

thanks

 

Jon

[Wristpin 400]

Fairly sure that you have an Atco / Qualcast / Suffolk A 98 engine which has Tecumseh ancestory. The early A 98s did use the same Zenith carb as used on the Suffolk cast iron engines and used the Suffolk flat pan muffler that yours has.

If you have a hot air gun or drop the carb bowl into a pan of boiling water for a couple of minutes and then grip the top of the jet with pliers and give it a gentle wiggle - they usually come out . A bit of grip damage to the top where you grip it won't do any harm as the calibrated bit is down the bottom . Poke through the orifice at the bottom with one bristle of a wire brush.

The return Spring is missing from your carb. It is a compression spring that sits between the cable abutment and the horizontally pivoted lever that has the governor Spring hooked to it, the cable passes through the spring.

I will post you a pic of the setup tomorrow , not good light in the shed and no flash on the iPad !

Should add that the early A98s with the Zenith carb had a points ignition system . When the Zenith was replaced by a Dellorto (or was it a Tillotson) the points were replaced with an electronic system.

Don't think you need worry about the brazing to the crank on the throttle spindle as the spindle and butterfly are both brass and if the repair had been done in situ the alloy of the carb top would have melted before any internal damage had taken place.

Edited October 7, 2015 by Wristpin

[jonnym 9]

Excellent advice/info.  I thought the engine was original and looked like the super model.  Even though it has the smaller engine it seemed to have bags of power.

 

It would be good to get the return spring on there so a photo would be great.

 

I forgot to mention it has odd wheels so need to look out for another wheel and assembly.  I might strip it over winter and repaint it as well.

 

Does anyone know where I could source spares for it?  The engine and carb are quite easy the rest is proving difficult.

 

thanks for the info

 

Jon

[Wristpin 400]

When Bosch disposed of the Atco / Qualcast / Suffolk brands the spares stock was bought by The Gateshead Mower Centre so they are possibly the first people to try for parts. May also be worth trying The Mower Centre in Hailsham.

http://www.themowercentrehailsham.com

Edited October 8, 2015 by Wristpin

[Wristpin 400]

Not the exact same engine as yours but the same throttle and governor layout.

Just noticed in one of your pics that there appears to be a chunk missing out of the recoil start housing. That may allow it to flex and the pawls to slip. Those housings are still available , also there's a fleabay seller offering complete starters at quite a keen price.

Edited October 8, 2015 by Wristpin

[jonnym 9]

Yes that spring is quite important, I hadn't realised there should be one there. I tried to over come the problem with cable ties, which works up to a point.

Yes the recoil start has seen some abuse but its not slipping currently, though it does need replacing. Do you have a link to the recoil start assembly on ebay?

Ive managed to free the jet using your hot water method. It was completely blocked. The Jet was a real pain to clear out but I managed it.

It hasn't helped the throttle problem however. I think the issue might be with the spring on the govener, as the bar which is brased in the photo, which opens the butterfly, never comes any where near close to the end of its stop adjuster screw.

This means when I'm setting the carb up the butterfly is always open too much. I need to fashion a spring to return it to its closed position to test my theory and if correct source another spring.

Still all in all not bad for £12.50!

Thanks again for all the help please keep it coming!

Sent from my GT-N7105 using Tapatalk

Edited October 8, 2015 by jonnym

[Wristpin 400]

Sounds as though the butterfly may have been removed during the brazing process (one tiny screw) and refitted incorrectly. The hole in the butterfly is not dead centre and the edges are slightly chamfered to allow it to close snugly in the venturi. Start by slackening the screw and seeing if you can align it. If it is the correct way up you may still be able to see an indented  mark on it that lines up with the shaft. Also there will probably be a "shadow" where it faces the shaft.

 

I'll have a look later for the starter.

 

This shows the mark on the butterfly - slightly askew! which should be parallel with the shaft and on the bowl side - and the offset of the hole which should be nearer the manifold than the bowl.

Edited October 8, 2015 by Wristpin

[jonnym 9]

Fantastic info again!

The photos are invaluable

I will whip it off and take a look tomorrow.

Thanks again

Jon

Sent from my GT-N7105 using Tapatalk

[Wristpin 400]

Starters

eBay . Just enter "Suffolk starter" . 261959754145 Is for a new housing at around £14 but there's complete assemblies for just under £20 which is a bargain as they are well over £ 30 trade.

[jonnym 9]

Thanks for the info once again.

I whipped the float chamber off the carb and took some photos of the accelerator all with the cable at the stop position resting against the electronic stop.

As you can see at rest the butterfly is wide open and the external bar is not returning to its closed position. In the other photo I'm closing the butterfly manually, it all looks to be lined up OK.

Where the different lenghts of springs which attach to the govenor? I'm I missing something?

Looking at how it all works using the choke to regulate the speed in the short term doesn't look like a dreadful idea, but I would prefer it working correctly.

Could you post a photo of your suffolk carb side on showing the spring etc.

Thanks again

Jon

Sent from my GT-N7105 using Tapatalk

Edited October 10, 2015 by jonnym

[jonnym 9]

Sorry for some reason tapa talk wouldn't upload the images.

Here they are.

Jon

[jonnym 9]

Ive had 20mins to have a play today and managed to cobble together a return spring as in photo. I did it just to prove to myself this was the issue.

It now revs with the accelerator.

So why is it not returning on its own? I'm guessing the governor spring should force it closed?

Heres a video showing it running, this was while still slightly cold and before tuning it. It's running far more nicely now, but I could do with being pointed towards a tuning guide to get it perfect. https://youtu.be/o9tYIAa91cM

Also see attached the plate on the engine just for nerd value.

Thanks again for all the help

Jon

Edited October 10, 2015 by jonnym

[Hillsider 16]

From your video it sounds as though you are getting there but your theory about the throttle butterfly actually works opposite to your thinking.

When the engine is at rest the light spring to the air vane will pull the throttle open allowing the engine to fire up but as soon as the engine is running air from the vanes on the flywheel blows against the airvane to close the throttle, engine speed is then controlled by tensioning the light spring connecting the vane to the throttle lever where the cable is attached. As the engine slows down when loaded air speed from the flywheel drops allowing the tension spring to to open the throttle further until speed picks up again allowing the engine to cope with changes of load when working. For this reason the spring over the cable is rather important, you could try a spring from a biro as an experiment but something a little stronger would be ideal, unfortunately the spring that you have fitted is not needed and should be removed.

Hope this help you to understand how the governor works if I have missed anything I am sure wristpin will fill in the gaps for us.

[Wristpin 400]

If you read Hillsider's explanation and assuming that your first picture illustrates the throttle cable in the closed position, that is slack enough that the horizontal "relay" lever is fully forward, the governor spring should be unloaded and exerting no pull on the link between the carburettor and governor vane but viewing the image it looks as though the coils may be slightly open suggesting that it is still under tension.

A compression spring in the correct position will ensue that the relay lever is fully forward which will allow the governor vane to act correctly rather than fight your improvised return spring on the carb. You can't expect the governor system to perform correctly unless it is correctly assembled.

[jonnym 9]

Yes all makes perfect sense now.  I will make up or find a  spring to test further, although using my finger to always apply pressure has no effect, I think the governor spring is also at fault (sorry to bang on about it).   I can see the spring has been pulled so it has open coils even unattached, also it is quite obvious the hook to the throttle has also been been made of one of the coils rather than a purpose built hook, so I think its been damaged and bodged.

 

I think this is why without my biro spring bodge its never returning far enough to allow the throttle cable to have any effect even with pressure applied to the throttle cable mechanism.

 

Ebay isn't any help for the governor spring any recommendations?

 

Thanks once again for all the help, it invaluable.

 

thanks

 

Jon

[Wristpin 400]

Ebay isn't any help for the governor spring any recommendations?

 

You'll possibly end up having to buy a pot of assorted springs unless you can find someone who already has!

I will post the correct part number later and it may be worth trying the Gateshead Lawnmower Centre or The Hailsham Mower Centre .

Also, tomorrow I will post the dimensions of the correct spring

[Wristpin 400]

Throttle return springs.

The original is shown as obsolete .

[jonnym 9]

Sorry for the late reply.

 

Thanks for the image, I made a spring to the dimensions in the image from welding wire which works temporarily and rotovated my mothering laws veg patch.  I won many brownie points and got to know the machine a little better.

 

I need to look at the carb again as I couldn't get it to run right at all, is the coke meant to be loose as it moved on its own while the engine ran.  I noticed when I bought it that the previous owner had positioned the air filter to regulate the choke!

 

More worrying is the fact that the small plate behind the exhaust leaks oil badly.  To remove it and reseal it I will have to remove the exhaust, which looks original and not an easy prospect.  Do these leak from there often?

 

Thanks again

 

Jon