Honda GX35 Bogging

[cory151]

Hey gang,

Just installed a new Honda GX35 on an all Aluminum framed cruiser. Only problem Im having is after warmup the motor bogs at WOT. Any ideas?

I experimented with oil levels full, half full, and 1/4 full because I read too much oil will cause a bogging issue. Next I tried better gas to no avail as well as removing the flame arrestor from the exhaust which just seems like a restrictive piece of a Brilo pad.

Plug looks really clean, the only thing you can adjust for the most part, seems to be the idle speed which does nothing.

 

[happyvalley]

If it's a new engine as you say, I would slow down first on the WOT then on trying a bunch of different things all at once because you might do more harm than good. Like for instance running with 1/4 oil. The GX35 is said by the manufacturer to be a 360* all position engine so oil level shouldn't matter. Besides in the pic yours looks mounted pretty level.

Take your time, break the engine in slowly, use the correct amount of oil, it's probably something simple like the air filter or fuel tank cap not venting.

 

[cory151]

If it's a new engine as you say, I would slow down first on the WOT then on trying a bunch of different things all at once because you might do more harm than good. Like for instance running with 1/4 oil. The GX35 is said by the manufacturer to be a 360* all position engine so oil level shouldn't matter. Besides in the pic yours looks mounted pretty level.

Take your time, break the engine in slowly, use the correct amount of oil, it's probably something simple like the air filter or fuel tank cap not venting.

Thank for the tip. Tried running with the fuel cap off and it didn't seem to matter as well as no air filter. So your suggestion is to drive the bike slower? Each thing I mentioned that I tried was completely independent of one another. Try something go for a ride. Didn't work return to stock, try something else, no better...etc etc.

This thing is on the clock. If it doesn't shape up its gonna find itself at the bottom of my recycle bin and be replaced with a Tanaka 40

 

[GearNut]

If things don't work out, could you please use my recycling bin? I'll even come over and get for you.

Try a new spark plug?
Check the color of the plug after an extended run time at full bog to see if it is rich or lean?

 

[cory151]

If things don't work out, could you please use my recycling bin? I'll even come over and get for you.

Try a new spark plug?
Check the color of the plug after an extended run time at full bog to see if it is rich or lean?

Heck no I made the mistake of letting somebody have my CNS carb that I offed once, only to go on a 60 mile ride with the guy and the CNS crapped the bed on the ride screwing me over yet again.

The plug on a lean tuned emission concerned 4 stroke doesnt tell you nearly as much as it would on a 2 stroke. Even if there was a mixture issue there are zero turnable screws on the carb. What would I do? Either way its actually a perfect looking plug after running the engine at WOT.

 

[hondabicycle]

Hello,
Did you try a differnet tension on the belt? I looked at the picture and it looks tight.

 

[cory151]

Hello,
Did you try a differnet tension on the belt? I looked at the picture and it looks tight.

Its got a factory installed tensioner that is spring loaded.

 

[happyvalley]

I can relate my experience with the same engine on the same drive set-up and say I've had excellent performance. Engine break-in I did was 10 hours, no WOT and varying rpms on a ride. I did a couple of oil changes in that time. Many users report a noticeable power increase after break-in and I agree with that, maybe as much as 20%. Though I infrequently run it wide open, maybe up a hill here and there, I have no issues with bogging, it will wind right through it's rpm range.

 

[hondabicycle]

I can relate my experience with the same engine on the same drive set-up and say I've had excellent performance. Engine break-in I did was 10 hours, no WOT and varying rpms on a ride. I did a couple of oil changes in that time. Many users report a noticeable power increase after break-in and I agree with that, maybe as much as 20%. Though I infrequently run it wide open, maybe up a hill here and there, I have no issues with bogging, it will wind right through it's rpm range.

Thanks happy.
His looks almost 45 degrees bend were the tensioner is. Is your tensioner about the same angle?

 

[zean]

Hi cory 151. I'm still learning about engines. I would check the valve train for bent push rods or stuck valves and valve lash. I would check the carb if bad gas plugged up the tiny passages, first I would put 3oz of gumout 2x concentrated fuel cleaner in about a 1/4 tank of fuel more or less, two or three times,and see if that would restore power. Thankyou.

 

[cory151]

I can relate my experience with the same engine on the same drive set-up and say I've had excellent performance. Engine break-in I did was 10 hours, no WOT and varying rpms on a ride. I did a couple of oil changes in that time. Many users report a noticeable power increase after break-in and I agree with that, maybe as much as 20%. Though I infrequently run it wide open, maybe up a hill here and there, I have no issues with bogging, it will wind right through it's rpm range.

Many people assume 4 stroke dont benefit (in power) from break in and I thinks thats not really true, It seems to be bogging slightly less than it did yesterday. Im gonna keep beating it to see if thats gets it broke in.

 

[cory151]

Hi cory 151. I'm still learning about engines. I would check the valve train for bent push rods or stuck valves and valve lash. I would check the carb if bad gas plugged up the tiny passages, first I would put 3oz of gumout 2x concentrated fuel cleaner in about a 1/4 tank of fuel more or less, two or three times,and see if that would restore power. Thankyou.

Fuel system cleaner did nothing and on the valve lash it checks out with a feeler gauge. The pushrods roll flat on a glass table.

 

[strotter]

No worries. I have built two Golden Eagle systems with GX35 engines. Both of them bogged at WOT until the motor was broken in. When you feel it bogging down, let up on the throttle. Keep doing that until the bogging stops. (only takes a few tanks of gas until it stops all together)

 

[cory151]

No worries. I have built two Golden Eagle systems with GX35 engines. Both of them bogged at WOT until the motor was broken in. When you feel it bogging down, let up on the throttle. Keep doing that until the bogging stops. (only takes a few tanks of gas until it stops all together)

Thanks Strotter, this is the info I was looking for. As evidence I have noticed this already happening. I feel like there is not a lot of information about these motors out there. Perhaps Ill start a new thread devoted to little things like this that I was unable to locate via Google.

Look for it.

 

[irishjedikev]

Hey Cory151....curious if this fixed itself or not. I'm having the same problem!!

 

[andrewflores17]

Mine came in the mail yesterday looks like a very well built little engine ill let you know if i have the same troubles here on the road .

anyone seen a upgraded car that may work on these things ?

 

[alexkram]

I realize I'm posting on a 2 year old thread but I fixed my Honda GX bog at WOT issue and I want to share how I did it for others with this problem. The bog was due to a lean condition. You can verify this by removing the air filter cover. Does it get worse? If it does it's too lean.

I took apart the carburetor and there is a pump in there with a diaphragm which presses onto a small steel lever. I bent the lever up just slightly so the diaphragm uses more of it's stroke. Bam, now it has MUCH better low RPM throttle response and no bog at WOT.

 

[sailorhuete]

With 250 hours on my honda it is now bogging all over the place. Full/part/mid it doesn't matter. I made sure cam timing is correct. I have a brand new air filter, spark plug and fresh fuel. I verified correct gap on the valves, the ignition coil and the pump in the carb. The spark plug does not look like i have been running a lean mixture. The oil is changed every 4 hours of riding. The exhaust valve has a lot of deposits on the stem and spring of valve inside of the head. Has anyone put any larger jets in the carb to solve the problem. I went from running at 8500 rpm to 6500 rpm in like 10 hours. Does this sound like a leaky exhaust or intake valve?

 

[GearNut]

With 250 hours on my honda it is now bogging all over the place. Full/part/mid it doesn't matter. I made sure cam timing is correct. I have a brand new air filter, spark plug and fresh fuel. I verified correct gap on the valves, the ignition coil and the pump in the carb. The spark plug does not look like i have been running a lean mixture. The oil is changed every 4 hours of riding. The exhaust valve has a lot of deposits on the stem and spring of valve inside of the head. Has anyone put any larger jets in the carb to solve the problem. I went from running at 8500 rpm to 6500 rpm in like 10 hours. Does this sound like a leaky exhaust or intake valve?

It sounds like the exhaust valve guide is leaking oil down onto the valve.
Is there alot of black, oily, scaly buildup inside the exhaust port too?

 

[Otero]

I experienced a similar problem with my GX35 after break-in. If in mounting
your Honda it got tilted far enuf for oil from the oil breather tube to saturate
the air filter the engine will run but suffocate at WOT. Also bad gas will clog
your gas filter even after it has evaporated out of the air filter. Clean your
air filter, dry it, and then check your fuel filter. If the fuel filter is brown,
chances are not enuf gas gets to the carb bogging it out. Replace filter.
Least ways, doing the above solved my problem.

Just an FYI, better late than never.