Help - Identical Engine, Slower Speed

[olddognewtricks]

HELP!! I need speed!!

I bought a new Harbor Freight Predator 212 a few months ago. I put it on the go kart kit that I built. With several speedometer apps, I consistently clocked it at 30 MPH on the same flat test road that I always use.

Recently, it started leaking oil. So, I returned it for a refund.

Then, I bought another brand new Harbor Freight Predator 212 (same model as before). I installed it on the same go kart. No other changes were made to the go kart.

With the new Predator 212, I can only max out at 25 MPH barely.

The throttle cable is tight. The speed limiter screw is backed out all the way. The throttle arm moves all the way to the fully open position.

When I "floor" the gas pedal, I can feel when the engine stops providing power. So, I am guessing the new engine is "tuned" a little differently from the factory. But, I want my speed back!!

Can anyone offer any suggestions on what can be tweaked or adjusted? I don't want to get into modifications such as high-flow air filters or removing the governor.

I am just looking for possible solutions with the existing setup with the OEM engine parts. Are there any simple ideas that might get me going closer to 30MPH again?

It seems like an identical engine should output the same speed.

THANK YOU!

 

[madtom]

The governor arm spring is probably adjusted a little different than the first allowing the first motor to rev a bit higher

Sent from my SAMSUNG-SM-G930A using Tapatalk

 

[olddognewtricks]

Thanks. Is there a way to adjust the governor arm spring to allow for higher revving? Would it need to be tighter or looser?

 

[Brianator]

Tighter, it should have multiple holes to move the spring into. Picture on it's way in a few...

Mine only has 2 holes but I've seen them with 3 and 6 also, there's nothing stopping you from drilling more either. On the other end of that spring there's a little "tang" that's connected to the throttle control lever, if moving the spring makes it rev TOO high bend it towards the governor to slacken the spring a hair and if it's still not enough you can bend it away to tighten it more. Minor adjustments make a BIG difference.

 

[olddognewtricks]

When the throttle is fully open (max speed), the governor arm does not have any more room to move forward. So, I guess I don't understand how tightening the governor spring can make a difference.

Are you saying that I should loosen the governor arm bolt and reset/re-tighten the governor arm in a higher revving baseline position ?

 

[Brianator]

No I wasn't saying that BUT it would be a great idea to reset the governor and make sure it's already at it's proper adjustment before you get hasty! In case you don't know how, it's easy... once you loosen the bolt turn the rod full clockwise then push the governor arm all the way over and tighten it back down.

If she's already maxed then I guess you could bring the rod a touch back CCW but remember, a little adjustment has a BIG impact and you'll want to be sure you're not over revving it or the governor "guts" will scatter!

Ah it! Just yank the assembly out and let those tires EAT! Valve float will protect the rest

 

[BigWes]

Those things aren't precision tuned from the factory. They are just basically bolted together and tossed in a box. That engine is quite capable of exceeding the rated governed speed and holding together. What are they supposedly governed to 3600 RPM? Pfft it'll easy run 5 grand without chucking parts. Snatch the gov... Brianator loves the smell of burning tires in the morning!

 

[Brianator]

Ya I do!

And the sound of a 2 stroke in the morning, gets me blood pumpin' every time!

 

[olddognewtricks]

The governor rod wouldn't budge even after loosening the nut. I'll probably make matters worse by trying again.

I wouldn't begin to know how to "chuck" the governor. Is it hard? What are the potential negative consequences? How is it done?

 

[Brianator]

It won't move either way? That sounds to be the issue!

Completely removing the governor by removing the main bits inside the motor, plugging the rod hole and rigging up a throttle cable and return spring will get you up to about 5500rpm safely. Use the search feature and look up "governor removal", the procedure on your predator will be the same as the hondas and clones of similar displacement.

 

[olddognewtricks]

That's too much work for me. I'll just ride this engine until it dies, then buy a Honda.

 

[Brianator]

A plan is hatched!

 

[JTSpeedDemon]

One thing that hasn't really been tossed around yet:

Did you buy the "EPA certified" version? They're designed to run lean for less emissions, but that kills top end power.

Either that or one of the two engines had a messed up governor.

 

[SteadyMobbin]

Possibly one is the hemi and the other is the non hemi version?

Removing the governor was easy as pie. The case ins't under pressure so you can just cap the hole where the governor was with a bolt and rubber o-ring. I just clipped the wires for the kill switch and left it in place.

It isn't hard. Im not very good with small mechanical parts and even I was able to do it. You'll be fine.

 

[JTSpeedDemon]

Hemi vs non hemi would NOT make that much of a difference, but the EPA certified one would be weaker.

 

[olddognewtricks]

I bought a Honda GX200 yesterday. It is notably slower, but it is so much nicer and more solid. Sort of like a Lexus versus the Predator which is fine but rough around the edges.

I might add a stage 1 performance kit.

I still have the Predator and will probably tinker with both engines and switch them out from time to time.

Are there any "controlled" test results for stage 1 upgrades that show whether or not the stage 1 kits actually improve horsepower or speed? Maybe I'll start a new thread on that question.

 

[JTSpeedDemon]

So let me get this straight:

Engine 1 (P212), got you to 30 MPH

Engine 2 (P212), got you to 25 MPH

Engine 3 (GX200), got you to 25 MPH

Is that correct? If so, I think it's safe to assume your first engine had a defective governor that let it rev higher than it should. I've heard of it with other engines.

 

[olddognewtricks]

Moving the governor spring to make the pull tighter, only made the go kart TAKE OFF as soon as I started it. Dangerous. So, I put it back to the original place. I don't know enough about small engines to be fiddling with that.

Tighter, it should have multiple holes to move the spring into. Picture on it's way in a few...

Mine only has 2 holes but I've seen them with 3 and 6 also, there's nothing stopping you from drilling more either. On the other end of that spring there's a little "tang" that's connected to the throttle control lever, if moving the spring makes it rev TOO high bend it towards the governor to slacken the spring a hair and if it's still not enough you can bend it away to tighten it more. Minor adjustments make a BIG difference.

Moving the governor spring to make the pull tighter, only made the go kart TAKE OFF as soon as I started it. Dangerous. So, I put it back to the original place. I don't know enough about small engines to be fiddling with that.

Tighter, it should have multiple holes to move the spring into. Picture on it's way in a few...

Mine only has 2 holes but I've seen them with 3 and 6 also, there's nothing stopping you from drilling more either. On the other end of that spring there's a little "tang" that's connected to the throttle control lever, if moving the spring makes it rev TOO high bend it towards the governor to slacken the spring a hair and if it's still not enough you can bend it away to tighten it more. Minor adjustments make a BIG difference.

 

[Brianator]

Something is amiss, can you provide a pic of where it was stock and where you put it? Moving it one hole to the "side" won't feel like there's a change by hand but you will notice less slack in the spring itself and it should "kick it up a notch" but not so much as you've described!

If you're not comfortable tweaking 'er then just enjoy it as is, no harm no foul right!?