thornhunter
New member
i have read that the carb on the 390 is small for that displacement.has anyone had any experience with replacing it?one article i read said the actual horsepower of that engine with the governor is 11 not 13.5.
honda gx390 carb
- Thread starter thornhunter
- Start date
- Status
Doc Sprocket
*********
Can you link the article?
I'm not entirely surprised though. A couple years ago, Honda "Officially" de-rated their engines to comply with regulations. The 390 went from 13 to 11, the 340 went from 11 to 9, etc.
From what I can tell, it is for the very same reason that Briggs engines are now marketed according to torque output, not hp anymore.
Since the governor limits RPM, it will limit peak net hp, as the peak does tend to be above 3600. However, I do not believe there's going to be a full 2 hp difference in an otherwise stock engine.
Smallish carb? Probably. An OEM manufacturer would have no reason to use a larger carb than necessary. AFAIK it's the same carb as used on the 340. As long as it will deliver the necessary mixture for the engine at the governed RPM, there's no reason to put on a bigger carb at the factory.
I'm not entirely surprised though. A couple years ago, Honda "Officially" de-rated their engines to comply with regulations. The 390 went from 13 to 11, the 340 went from 11 to 9, etc.
From what I can tell, it is for the very same reason that Briggs engines are now marketed according to torque output, not hp anymore.
Since the governor limits RPM, it will limit peak net hp, as the peak does tend to be above 3600. However, I do not believe there's going to be a full 2 hp difference in an otherwise stock engine.
Smallish carb? Probably. An OEM manufacturer would have no reason to use a larger carb than necessary. AFAIK it's the same carb as used on the 340. As long as it will deliver the necessary mixture for the engine at the governed RPM, there's no reason to put on a bigger carb at the factory.
OzFab
Well-known member
Honda GX140, 160 & 200 all use the same carb with different jets so, logically speaking, a GX200 carb on a GX140 will perform better. However, delivering too much fuel is just as bad as not delivering enough.
Having said that, if you wind out the mixture screw & find the engine runs better, you may find a bigger jet will be worthwhile.
A bigger carb would depend on the size of the intake port; if the carb bore is larger than the port, it's wasted; if it's smaller, it's starving...
Having said that, if you wind out the mixture screw & find the engine runs better, you may find a bigger jet will be worthwhile.
A bigger carb would depend on the size of the intake port; if the carb bore is larger than the port, it's wasted; if it's smaller, it's starving...
thornhunter
New member
i found the article surfing,so it would hard to find.im a old dirt bike rider that has gone to honda atc.maybe im expecting too much.our local sand strip is dialin so maybe i should concentrate on consistency not on speed.this is my frist cart in over 50 years.
- Status