H-Towner
Forum Newbie
- Joined
- Jul 20, 2024
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- 5
Hi, new to the forum and a novice at small engines. I have a Coleman Powermate 4000 (PM54-4202) powered by an 8hp horizontal Briggs & Stratton engine (194412-1112-01). This was gifted to me by a friend, and when I tried to use it several years ago, the engine surged a lot and threatened to stall unless I partially closed the choke. I put it aside then, and it has since sat in my garage unloved, but I’m motivated now by Hurricane Beryl to get it going if I can. There’s a lot of good and bad information online, and I’ve learned a fair bit, but I could use the benefit of other people’s experience. I’m going to dump a lot of questions here, and I hope that’s alright.
As I understand it the issue before was probably the engine running lean, thus by adjusting the choke I restricted the intake air and helped balance the mixture. So I extracted the needle valve and main jet, cleaned them, and reinstalled, first seating the needle valve, then backing it out 540° (1-1/2 turns). I put some new gas in it and ran it a bit with the air filter off, periodically spraying carb cleaner into the intake. After all that (some of it possibly unnecessary) it seems to run smoothly under no load.
I wanted to test the voltage before powering anything with it, and I got a reading of 130v from the 120v outlet. My first thought was maybe the voltage is too high because the engine rpms are too high, but my second thought was monkeying with rpms will probably affect the a/c frequency.
So my first question is what is likely causing voltage to run hot, and what’s the proper way to correct it?
Following that, how do I check engine speed to verify it’s running at the 1750 rpms called for in the manual? I see lawn mower repair videos where they’re holding some kind of touch free tachometer near the spark plug wire. I have to figure it’s counting spark plug firings by reading the em field like a clamp ammeter. Is that how one would measure engine speed on this unit?
Other questions regarding carburetor adjustment:
I’m guessing that having no load, the engine is running at idle, yet the idle set screw is not resting on the throttle stop. Should it be?
The “Final Adjustment” section of the B&S manual says to put the throttle control in fast position while adjusting the main jet’s needle valve. The generator doesn’t have a user operated throttle control. Should you perform this step after putting a load on the generator, like a space heater? Or do you just hold the throttle open with one hand while turning the needle valve with the other?
Thanks in advance to anyone who read this far, and especially if you were able to answer a question.
![IMG_8035.jpeg IMG_8035.jpeg](https://www.lawnmowerforum.com/data/attachments/58/58117-de00cc9e0030a00a285c277cdeefc77e.jpg)
![IMG_8036.jpeg IMG_8036.jpeg](https://www.lawnmowerforum.com/data/attachments/58/58118-675b447298b4616d2fc334ba19c87b32.jpg)
![IMG_8040.jpeg IMG_8040.jpeg](https://www.lawnmowerforum.com/data/attachments/58/58119-c43f9f993e37fece6fc70d72e9395311.jpg)
![IMG_8041.jpeg IMG_8041.jpeg](https://www.lawnmowerforum.com/data/attachments/58/58120-d3b5a2e4eb16ada524360c7a1736f73a.jpg)
As I understand it the issue before was probably the engine running lean, thus by adjusting the choke I restricted the intake air and helped balance the mixture. So I extracted the needle valve and main jet, cleaned them, and reinstalled, first seating the needle valve, then backing it out 540° (1-1/2 turns). I put some new gas in it and ran it a bit with the air filter off, periodically spraying carb cleaner into the intake. After all that (some of it possibly unnecessary) it seems to run smoothly under no load.
I wanted to test the voltage before powering anything with it, and I got a reading of 130v from the 120v outlet. My first thought was maybe the voltage is too high because the engine rpms are too high, but my second thought was monkeying with rpms will probably affect the a/c frequency.
So my first question is what is likely causing voltage to run hot, and what’s the proper way to correct it?
Following that, how do I check engine speed to verify it’s running at the 1750 rpms called for in the manual? I see lawn mower repair videos where they’re holding some kind of touch free tachometer near the spark plug wire. I have to figure it’s counting spark plug firings by reading the em field like a clamp ammeter. Is that how one would measure engine speed on this unit?
Other questions regarding carburetor adjustment:
I’m guessing that having no load, the engine is running at idle, yet the idle set screw is not resting on the throttle stop. Should it be?
The “Final Adjustment” section of the B&S manual says to put the throttle control in fast position while adjusting the main jet’s needle valve. The generator doesn’t have a user operated throttle control. Should you perform this step after putting a load on the generator, like a space heater? Or do you just hold the throttle open with one hand while turning the needle valve with the other?
Thanks in advance to anyone who read this far, and especially if you were able to answer a question.
![IMG_8035.jpeg IMG_8035.jpeg](https://www.lawnmowerforum.com/data/attachments/58/58117-de00cc9e0030a00a285c277cdeefc77e.jpg)
![IMG_8036.jpeg IMG_8036.jpeg](https://www.lawnmowerforum.com/data/attachments/58/58118-675b447298b4616d2fc334ba19c87b32.jpg)
![IMG_8040.jpeg IMG_8040.jpeg](https://www.lawnmowerforum.com/data/attachments/58/58119-c43f9f993e37fece6fc70d72e9395311.jpg)
![IMG_8041.jpeg IMG_8041.jpeg](https://www.lawnmowerforum.com/data/attachments/58/58120-d3b5a2e4eb16ada524360c7a1736f73a.jpg)