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Old 11-29-2019, 12:34 PM
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Default Briggs 8 horse

Well I just found out that my uncle has a briggs 8 horse in his garage that he was planning on using on a go kart for his son. Both of us agree that 8 horses is a bit too big for a small kart for an 9 year old. So I asked him how much he wanted for it, since I've been looking for one for my streaker, and he said he'd get back to me.

So, question one, is there anything I should know about these engines throttle hookups beforehand?

Question 2 do these have a 3/4" or 1" shaft (I'm thinking 1" but I'm not sure)?

Question 3, Should I keep using the 30 series with a new driver if it's a 1", or should I put it on my drifter, and run a 20 series. I've heard they were designed for go karts, and that it should be more like the original setup.

And question 4, do 8 horse briggs's have a similar mounting pattern to a predator 212 (the current engine, which is straining a little bit). The only measurement I'm worried about is the width. The slots are long enough (2 1/2" ish).

Here's a pic of the kart, though It's been on here plenty. I really need a new pic, this is when it still had the tecumseh on it and the old 30 series.
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Old 11-29-2019, 06:41 PM
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Budget GoKart will probably be able to help with the mounting pattern.
It'll most likely have a 1" shaft, but measure it. These engines were used on so many applications, sometimes the shafts are too short or a wacky diameter like 1 1/8".
Most 319cc(?) flatties have Flo-Jets like my 5 HP, so I can help with throttle linkage and the likes. The flathead service manual goes well into details as well, I can share that with you.
I wanna see some pics!
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Old 11-29-2019, 07:53 PM
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I'll get some pics when I get the engine. Should be sometime around Christmas, maybe sooner. But depends on the price. So what would be a good price for this engine. I know briggs 5hp's are usually asking $30-$40, but I haven't seen any 8 horses for sale. I'm thinking $50 would be about it.
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Old 11-30-2019, 06:57 AM
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Depends on if it's running or not!
We need a LOT more details to help give a quote. My solid but non sparking 3 HP was $30, if that helps you calibrate at all.
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Old 11-30-2019, 04:07 PM
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If it runs 60$ if not 30$ the engine needs new mounting holes unless you have a jackshaft or move able sprocket but it uses the same bolt pattern as a 212 usually also it should have a 1 inch shaft you can get and industrial clutch on ebay for 50$ or attempt to adapt a tc usually they don't fit though
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Old 11-30-2019, 05:50 PM
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BMIKarts sells 30 series drivers with a 1" bore. And 8 HP is within the max RPM limit to boot!
At least, until you hop it up......
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Old 11-30-2019, 06:58 PM
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Ok, that price is within my budget. The mounting might be a problem. I hope you mean the Briggs 8 horse is wider than the predator. The kart has a 30 series tav kit on it, so the sprockets donít move much. It I think it had something bigger than a 212, because both the current 212 and the ohh60 were about 3/16Ē to 1/4Ē too far right to get the proper chain alignment. I had to use spacers on everything, the driver and the driven, and I had to add some washers behind the backplate. Itís still a bit off, but itís acceptable. So maybe the bigger engine will get it in proper alignment. And a centrifugal clutch isnít even an option for this thing. The kart alone probably weighs 300, and I weigh 150. Also it has 6.6:1 (9t TC sprocket 60t axle sprocket)gearing and 22Ē tires. And no, it has a differential with an 8 bolt sprocket, so I canít swap it easily. And if I get it the Briggs will stay stock, Iím looking for torque, not speed. Itís fast enough.

---------- Post added at 08:58 PM ---------- Previous post was at 08:11 PM ----------

Quick question, are there any charging systems for these engines?
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Old 12-01-2019, 07:34 AM
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When you get it, send me the codes and I think I can get you a PDF copy of the parts manual. In my parts manual at least, it also shows the electric starter and alternator parts even though it's equipped with a recoil. So with a parts manual, you should be able to piece together a charging system and e-start. WARNING: This may be pricey, not to mention possible hard to find parts.

I'd love to do an e start conversion on a flathead, but I don't want to meddle with my HiPo.
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Old 12-01-2019, 11:08 AM
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I have an 8hp and you almost can't get one with a shaft that fits a tc you may have to make an adapter or drill and tap the end of the shaft
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Old 12-01-2019, 12:17 PM
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I have an 8 horse with the end drilled and tapped already and it's a 1 inch shaft. So yes they can be 1 in. Shafts and even thought it was said above, the bolt pattern is wider and longer.
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Old 12-02-2019, 06:37 AM
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Ok, so if the end isn't drilled and tapped, can I drill it using any old lathe, or does it need to be something special? I will be getting an older lathe soon. And if it has a weird shaft size (like a 7/8 or 1 1/8) can I turn it down on the lathe to the correct size, or will I need to take it to a machine shop?
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Old 12-02-2019, 07:14 AM
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Take the crank out it will be very quick and easy like cars a d cameras did to their Subaru
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Old 12-02-2019, 08:11 AM
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Yeah, taking the crank out first is kind of common sense. And those guys are good for entertainment with a few laughs, but they're not the best role models. And I'll see about getting the mounting hole dimensions off the kart.

And I found this.
Apparently theirs had a 9hp flathead. So I'm thinking the 8 horse will fit. The karts the same ad mine, as far as I can tell, just has a different front end.
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