5hp briggs flathead advice

[Kansaskart]

Gotta manco 3 wheeler with one of these. Its goverened. Of course, I want to remove the govenor. So, I will run it hard but not leave it wide open for long periods. Question is how well do these hold up or should I put a billet rod in it and would the rod be enough with the standard crank and piston? Im not trying to build a race machine just want it to move faster and not blow up. I used to run 8hp briggs pretty hard but that was 35 years ago, never ran a 5hp. Actually a 8hp would fit on this but im just trying to simplify things. Just use it to run up and down the roads.

I like the look of it, would rather not put a clone on it if I dont have too.

---------- Post added at 02:19 PM ---------- Previous post was at 02:02 PM ----------

Found the rod that works with the stock piston and rod, $70. Or 3/4 the price of a clone. Im just getting bored seeing 212s slapped on everything im surprised granny doesnt have one on her cake mixer.

 

[KingCobra]

Instead of removing the governor, can't you put a zip tie through the spring and secure it so the governor is more or less disabled that way and the spring can't expand? Good luck on that Briggs.... IMO Briggs is junk and I won't run them after I lost one after about 10 hours of running when I found out they use poly inside the engine!! Example is a POLY Timing gear, etc. I'm also sore at Briggs after what they did to Murray. They knew they had competition!! BTW, look what I got.......

 

[Kansaskart]

Lol, hillarious. Thx.

I actually have a gx390 sitting right next to it. That would be interesting.

 

[Kartorbust]

Instead of removing the governor, can't you put a zip tie through the spring and secure it so the governor is more or less disabled that way and the spring can't expand? Good luck on that Briggs.... IMO Briggs is junk and I won't run them after I lost one after about 10 hours of running when I found out they use poly inside the engine!! Example is a POLY Timing gear, etc. I'm also sore at Briggs after what they did to Murray. They new they had competition!! BTW, look what I got.......

That's funny because I've never had issues with Briggs engines, only Tecumseh and it's always carburetor related.

I'd keep the Briggs and get better internals for it.

 

[karl]

my flathead eats predators.

stock rod is good for stock valve springs.

I got a nos briggs motorsport rod for $9 on ebay. Find one if you want to push it hard.

A cam wakes them up.

The factory cam is all steel in flathead 5hp motors, dont know why you would mention plastic cams. Predators had plastic cams too.

 

[Kansaskart]

Thx. Ditto on the tecumsehs.

I just dont want to end up with a ultra expensive engine. First a rod. Now the cam sounds good. Dont tell me whats next lol.

 

[KingCobra]

my flathead eats predators.

stock rod is good for stock valve springs.

I got a nos briggs motorsport rod for $9 on ebay. Find one if you want to push it hard.

A cam wakes them up.

The factory cam is all steel in flathead 5hp motors, dont know why you would mention plastic cams. Predators had plastic cams too.

I agree but that all changed with the Gen II or III Pred engines I believe. My Briggs engine was produced for Troy Bilt for use in their pressure sprayers. Still no excuse to use poly parts inside an engine. ( You Tube<> Look it up) It was a 6.75 hp engine. What a screw up that was. I make sure I don't buy the GEN I Preds........


https://www.youtube.com/watch?v=trlUOo2ykVg

 

[Hellion]

You can run that engine minus the governor, provided you retain everything else as stock. The engine will reach a natural rev limiter in the form of valve float long before any chance of catastrophic engine damage. A billet/forged connecting rod is a good idea though as it is any engine's weakest link.

...IMO Briggs is junk and I won't run them after I lost one after about 10 hours of running when I found out they use poly inside the engine!! Example is a POLY Timing gear, etc. I'm also sore at Briggs after what they did to Murray...

Man, that's some issues. I can feel the hatred flowing through you, I mean the butt hurt.
You've got a major axe to grind with B&S and I don't think there's much of anything we can do except to suggest you stay away from all threads with Briggs in the title. I am praying for you buddy and I hope that you can let it all go one day....

I'm sorry you used one of Briggs's "economy model" vertical shaft pressure washer engines on your go kart or mini bike, and experienced a failure. I'm not really surprised. Those are not recommended for motorsports. Any flathead horizontal shaft engine, typically the 5 HP 130000 series, is your best bet (even the exalted Raptor). All metal parts too (aside from the governor gear, a low stress part).

 

[Kansaskart]

So do they generally remove the plastic gov gear inside? I probably wont, really dont want to dismount, etc, its running good right where its at.

I see these engines often for not much $ so not super worried more so curious. No problems with frequent oil changes im pretty good there. I just picked up a new kart with a 5hp on it, considering a predator on it, could take the 5 off it and build it some and have for a backup.

Also, I know about the valve float on the predators but didnt know on briggs.

 

[Kartorbust]

Technically all engines will float valves, just have to spin it up to that point.

 

[KingCobra]

Technically all engines will float valves, just have to spin it up to that point.

Hence, the reason for a 'governor'.......... BTW, 'floating valves, I hear, are not a good thing either. Is that correct? I've never had it happen,but then again, I've never had a governor that caused me pain and sorrow.............. As far as the 'floating valve' syndrome 'after' governor loss........what really else does go on while that is happening.......hmmmmmmm.. I say just locate the spring and run a zip tie through it and secure it and see how you like it before going through the trouble.

Man, that's some issues. I can feel the hatred flowing through you, I mean the butt hurt.
You've got a major axe to grind with B&S...........

Yes, and rightfully so and you would feel the 'butt hurt' too if the replacement parts for your cart don't exist because BS destroyed them....Luckily they are ALL easy to duplicate..... And it's 'AX' not 'axe'......... And no, no more vertical shaft BS engines for me....... BTW, I had one of these on my mini bike as a kid, governor was a pain and it's probably in a museum by now........

https://www.youtube.com/watch?v=jbSjWvfBdBU






https://www.youtube.com/watch?v=8xp513KHQQo

 

[bob58o]

Im just getting bored seeing 212s slapped on everything im surprised granny doesnt have one on her cake mixer.

https://www.youtube.com/watch?v=Z12gbY3nTm0

 

[Kartorbust]

https://www.youtube.com/watch?v=Z12gbY3nTm0

Bet it could rip stumps out of the ground, without breaking a sweat.

 

[bob58o]

Valve float is when the RPMs are too high and the valve springs do not provide adequate pressure to correctly close and seal the valves. It also has a lot to do with the profile of the cam lobes. Camshaft and valve springs will determine what RPM you can spin to before the valves no longer close and seal properly.
https://www.youtube.com/watch?v=_REQ1PUM0rY

 

[OzFab]

Instead of removing the governor, can't you put a zip tie through the spring and secure it so the governor is more or less disabled that way and the spring can't expand?

This is a sure fire way to destroy an engine; when the governor gear explodes it will take out the internals (con rod, crank, etc)...

 

[KingCobra]

I sure am relieved that someone answered my question before someone tried it then. Thanks!!

 

[Kentucky Boy]

Put a rod in it.

 

[anickode]

https://www.youtube.com/watch?v=Z12gbY3nTm0

With a big enough gear ratio a little bit of power can go a long way. It's stuff like this that makes the idea of "horsepower" make way more sense. A team of 6 horses could probably eek a semi along at 1mph.

There's a guy on YouTube that builds gearboxes with insane gear ratios just for the sake of it. He built one that's like 13 trillion to one, which (in a ideal friction free world), if you were to put a 6" hamster wheel on the input shaft with a single ant running on it (again, zero friction), would yield like 36,000 TONS of pulling power. It would also translate to well over 800 years to achieve a single rotation of the output shaft at a 30,000 rpm input speed.