suffolkpunchman
Forum Newbie
- Joined
- Jun 23, 2023
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- 2
Hi everyone,
Picked up a Qualcast Suffolk Punch 30 a couple of weeks ago off Facebook Marketplace. Can't find any builders plates or info anywhere on the mower, apart from the grass box having a green sticker that says "Qualcast Suffolk Punch 30" on it. I assume this is the grass box it had from new but I've attached photos in case this isn't correct and it needs identifying. However, the petrol tank is on the handlebars, with the Zenith carburettor.
When I went to pick the mower up the owner showed me it starting up etc, and it ran really nicely. However, it was running as fast as you'd ever want to run it with the throttle lever on the handlebars barely cracked open, and there was no way to get it to idle.
So, having stripped, cleaned, and adjusted the carburettor to the manual's instructions (3/4 turn out from fully seated for main running speed screw and 1 turn out from fully seated for the idle speed screw) it will now idle, however, full speed now sounds inconsistent and not smooth at all. It's not revving up and down / surging, but the tone of the engine and the exhaust just sounds, well, awful to me.
The exhaust sounds quite loud and makes 'putt' noises sometimes, feeling the exhaust, the blast of the exhaust gasses against my hand is consistent, but the engine doesn't sound smooth at full speed. It just doesn't sound happy, consistent or how an engine should sound to me. It sounds rough.
I know these engines run beautifully when all tuned up as per dozens of YouTube videos but mine won't seem to be consistent at full speed (a sensible 'full speed', not revving the engine as far as it will go, may I add).
Some things I would like some answers to are (in addition of course to any suggestions and advice you have to get the mower running better):
1) How should the throttle tensioner be set?
2) There is a small arm with a screw and spring that touches the carburettor and then swings away when the throttle is opened. This hasn't been mentioned in any manuals I've read or any videos online. How should this be adjusted?
3) The spark plug on the mower turns very black and carbon-y after a short period of running (was clean before today and a half-hour of running has it looking like a piece of coal!) I understand this is due to the mower running rich, but how do I adjust this (without the mower revving too high?)
I'm ordering new gaskets for the cylinder head, carburettor and exhaust and I'll be changing the oil and spark plug as well. I doubt this will help much as they're not damaged, just very old, and like the rear roller drive belt, look to have been on there for donkeys years!
There's my plea for help, and thanks in advance for all your help. Let's get this beautiful old machine working right again!
Picked up a Qualcast Suffolk Punch 30 a couple of weeks ago off Facebook Marketplace. Can't find any builders plates or info anywhere on the mower, apart from the grass box having a green sticker that says "Qualcast Suffolk Punch 30" on it. I assume this is the grass box it had from new but I've attached photos in case this isn't correct and it needs identifying. However, the petrol tank is on the handlebars, with the Zenith carburettor.
When I went to pick the mower up the owner showed me it starting up etc, and it ran really nicely. However, it was running as fast as you'd ever want to run it with the throttle lever on the handlebars barely cracked open, and there was no way to get it to idle.
So, having stripped, cleaned, and adjusted the carburettor to the manual's instructions (3/4 turn out from fully seated for main running speed screw and 1 turn out from fully seated for the idle speed screw) it will now idle, however, full speed now sounds inconsistent and not smooth at all. It's not revving up and down / surging, but the tone of the engine and the exhaust just sounds, well, awful to me.
The exhaust sounds quite loud and makes 'putt' noises sometimes, feeling the exhaust, the blast of the exhaust gasses against my hand is consistent, but the engine doesn't sound smooth at full speed. It just doesn't sound happy, consistent or how an engine should sound to me. It sounds rough.
I know these engines run beautifully when all tuned up as per dozens of YouTube videos but mine won't seem to be consistent at full speed (a sensible 'full speed', not revving the engine as far as it will go, may I add).
Some things I would like some answers to are (in addition of course to any suggestions and advice you have to get the mower running better):
1) How should the throttle tensioner be set?
2) There is a small arm with a screw and spring that touches the carburettor and then swings away when the throttle is opened. This hasn't been mentioned in any manuals I've read or any videos online. How should this be adjusted?
3) The spark plug on the mower turns very black and carbon-y after a short period of running (was clean before today and a half-hour of running has it looking like a piece of coal!) I understand this is due to the mower running rich, but how do I adjust this (without the mower revving too high?)
I'm ordering new gaskets for the cylinder head, carburettor and exhaust and I'll be changing the oil and spark plug as well. I doubt this will help much as they're not damaged, just very old, and like the rear roller drive belt, look to have been on there for donkeys years!
There's my plea for help, and thanks in advance for all your help. Let's get this beautiful old machine working right again!
