Qualcast Suffolk Punch 35s

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joe44
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Qualcast Suffolk Punch 35s

Postby joe44 » Fri Oct 30, 2015 8:31 pm

Hello new to the forum, hoping someone can help me with this problem I have with my lawnmower.

The lawnmower is an a114 aluminium engine and has the Dellorto carb, mechanical governor, and two pole ignition coil so I reckon that it's late 80's maybe 1988, anyway the problem is the recoil starter keeps slipping when trying to start the mower, its so bad that you can see the engine cowl bulge and the plastic starter housing coming away from the engine cowl.

One of the starter pawls then comes out of the starter cup and then the whole thing gets jammed up and has to be removed.
Even with the spark plug removed it still doesn't seem to engage very well.

Compression is 90psi so I don't think that should cause it to struggle.
I've rebuilt the starter and still the same problem, the pulley does seem to have quite a bit of play so maybe the starter housing is warn any ideas?

Thanks Joe
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Beagle2
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Re: Qualcast Suffolk Punch 35s

Postby Beagle2 » Tue Dec 08, 2015 6:18 pm

Hi Joe,

Do the pawls and engagement plate look worn?

Are you certain the recoil was rebuilt with suitable spring tension?

Jamming recoils can me a misery...

If it's the model I'm thinking of, you can still buy the recoil assembly new.

Ebay have them for circa GBP 20.

Do you have a pic?
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joe44
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Re: Qualcast Suffolk Punch 35s

Postby joe44 » Sun Jan 03, 2016 1:33 pm

Hi Beagle2 thanks for the reply,

I've fixed this problem, the bottom two bolts holding the cowling to the engine had stripped threads (a common problem I'm encountering on this mower) so i tapped them to a bigger bolt and this pushed the cowling slightly out of line with the engine, after enlarging the cowling holes i was able to align the cowling with the engine and all engages well now.

The current problem I'm having is a weak spark using the resistor cap, I get a strong spark from just the HT lead.
I've had the flywheel off and the Stator coil did have a crack in the casing which i sealed up, the mower struggles to start from cold and cuts out when the revs are increased or the choke fully open, and struggles to restart from hot, also the spark plug when pulled is always wet as if the fuel mixture isn't burning properly, the carb is clean and seems to be set up correctly. When running the engine produces a strong smell from the exhaust but it does not produce any white smoke, so I'm not sure if it's burning oil.


Thanks again for you're help

Joe
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cancunia
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Re: Qualcast Suffolk Punch 35s

Postby cancunia » Thu Jan 07, 2016 10:35 am

Joe,

It does sound like your coil is failing, have you tried running without the suppressor cap? I've read on other engine forums that magnetos don't go too well with suppressor leads or caps as it puts too much strain on the coil. From what I've also read elsewhere the need for suppressors to stop radio interference is largely a thing of the past. Your local experience may well be different, but it's maybe worth a try. I have no experience of Suffolk engines, so am not sure if new coils are available?

I'm not sure if you'll be interested in this?

http://www.stationary-engine.net/forum/ ... post235922
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joe44
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Re: Qualcast Suffolk Punch 35s

Postby joe44 » Sat Jan 09, 2016 2:25 pm

Hi cancunia,

Thanks for the reply,
Ignition stators are readily available for about £50 they are non original made under license from the original manufacture which was Wipac, so they are probably as good as an original.
It's a reasonable price if it fixes my problem, I'm pretty sure the coil is at fault just wanted to see if anyone else agreed.

As regards to radio interference i agree i don't think that is an issue anymore, my rotary mower with an sv 150 engine does not have a suppressed cap or spark plug. using a multi meter measuring resistance on the sv 150 coil i get 6k ohms and this coil produces a very strong spark, on the Suffolk coil i only get 1.3k ohms, I've read between 2.5k and 5k ohms indicates a working coil, I'm not sure if this is an accurate test because I've also read that this test only works on the old style magnetos not the more modern one piece ignitions without points known as solid state or CDI.

Was the radio interference the only reason they suppressed the spark?
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cancunia
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Re: Qualcast Suffolk Punch 35s

Postby cancunia » Sun Jan 31, 2016 1:24 pm

I've heard various stories about suppressor caps, including that they help build up the voltage at the plug. However, the name says it all for me, they suppress RF emissions. My Villiers C12E Handbook says to use a plug with a resistor and a straight through cap, maybe that's the voltage build up aspect. It's been a while since I first replied, so maybe you've got it all sorted by now?
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joe44
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Re: Qualcast Suffolk Punch 35s

Postby joe44 » Fri Feb 05, 2016 7:01 pm

The mower only seems to work on the suppressed cap so maybe it does build up voltage, when I shut the engine off and pull the plug the piston is wet and shiny i assume this is oil as it doesn't evaporate if left a while, the cylinder is smooth not a scratch on it, but the piston and valves have slight play does this look like the piston rings or valve guides are letting oil through?
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cancunia
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Re: Qualcast Suffolk Punch 35s

Postby cancunia » Sat Feb 06, 2016 9:05 am

I'm no expert with these engines, so my thoughts are quite generic, based on what you've written:

1, how easily does it start & run?
2, when you take out the plug, what colour are the electrodes, are they clean?
3, does the engine smoke when running?
4, It seems odd that it won't run without the cap, did you try a new plug?
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joe44
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Re: Qualcast Suffolk Punch 35s

Postby joe44 » Sat Feb 06, 2016 4:14 pm

Ok

1, Most of the time it starts easy but sometimes wont start, when it's running it maintains revs well and accelerates and runs well.
2. Electrodes are black.
3, Slightly when going from idle to full throttle but clears quickly.
4, It tries to start but fails to get going haven't tried new plug, the plug i have is an NGK b6s about a 3 months old probably seen an hours use.

To me it looks like it's burning oil maybe passing through the piston rings, compression is a consistent 90 psi so i thought maybe it's got to much oil or poor quality oil or it's coming through the valve guides.

Once again thanks for the help.
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cancunia
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Re: Qualcast Suffolk Punch 35s

Postby cancunia » Sat Feb 06, 2016 4:52 pm

Certainly sounds like it may be oil from your description of the plug. Maybe an oil change would help? You may also want to consider running a hotter plug, maybe B4-LM (LM for LawnMower btw). From some reading I did on Briggs engines a while ago, it seems that Briggs now specify B4 plugs as opposed to the B6 plugs that they specified a few years ago due to the changes in fuel. A hotter plug may well also burn off deposits better. I have a Howard Bantam with a Villiers C12 engine (for sale if anyone's interested), which was hard to start after a couple of hours running even after cleaning the plug, I put a hotter plug in and so far it starts ok. Might be worth checking that the B4-LM is the same size and depth of thread before buying one.
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robo
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Re: Qualcast Suffolk Punch 35s

Postby robo » Sat Feb 06, 2016 5:27 pm

I thought villiers only made two strokes, at least all the bikes I had with villiers engines where two strokes
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cancunia
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Re: Qualcast Suffolk Punch 35s

Postby cancunia » Sat Feb 06, 2016 5:31 pm

Yeah, bikes for sure almost certainly 2 strokes in my experience too, but stationary engines were almost always 4 stroke.
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joe44
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Re: Qualcast Suffolk Punch 35s

Postby joe44 » Tue Feb 16, 2016 10:19 pm

I have now removed the piston from this engine to find that the piston skirt has a few vertical scratches that can be felt easily by hand and the bore has slight vertical lines but is smooth to the touch.
The bore is very smooth which I initially thought was good but after researching this, it is what's known as bore glaze and at the very least the cylinder would need to be honed for new rings to seat.

After checking the piston ring gap the top compression ring was .60 of a millimetre, the second and oil ring were worse at nearly .90, the service manual says it should be between .015/0.38, so either the rings are worn, the piston as well or the bore, or a combination of all 3. the piston did have slight play so I would thinks it's not just the rings, I guess new rings would tell me the answer to that question. Does anyone have any experience in this kind of job?
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