I have a Rubicon that is used as a workhorse. I train Gundogs and this machine is hauling or pulling somthing nearly everyday. No pleasure riding here. I have had issues with it starving for fuel and quit running lately, let it sit a few min. and it cranks back up and runs fine.
It seems to do it when there is a increased demand for fuel and I have noticed that it seems to be getting hot but the warning light dose not come on (I know the light works because it lights up when you first turn on the ignition during startup then goes off)
I have replaced Air Filter, Spark Plug and removed the Carb. and cleaned with carb cleaner and blown it out with compressed air I have also removed the fuel tank and cleaned it out. All runs fine until I put it under a load and get it good and hot then we have problems again.
The cooling fan is coming on but I do not know if it is cycling like it should (should I install a toggle switch and manually run the fan all the time when working hard?)
I have also noticed that it dose not idle very smooth and will sometimes die and this is worse if it is hot.
I have cleaned the carb once and the honda shop has rebuilt it once with no change in performance. Do I need a new carb? and if so which one?
I have also tried hot and cold plugs with no change in performance.
Still runs better than my brothers polaris.

Any suggestions?

Thanks,

Rich

 

Have you checked to see if there is any restriction in the exhaust/spark arrestor?

 

I pulled the spark arrester out when it was new to keep it from clogging up. Last time I checked it on the work bench it still looked great.LOL I have not thought to chech the muffler system but I would think that a restriction would be unlikely but I could be wrong. That's about the only thing I have not checked yet so I might as well. I have been scratching my head on this one for some time now.

 

So basically you think it's starving for fuel when under a load?

If so I'd wonder about something restricting fuel flow into the float bowl. Was the float level within spec? Did you pull the screen in the tank and check it?

Cooling fan wise, a bypass switch is a popular mod, but as long as the thing isn't overheating I don't think I'd worry about it.

Also, have the valves been checked? The last time I did a Rubicon, the valves were tighter than spec...

Anyway, welcome to the forum.

 

air vent tube?

 

Air vent tube on fuel cap has been checked and is not clogged.
The second time I pulled the carb. off I had the Honda shop rebuild it so that things such as float level could be checked by somone who (is supposed) to know what they are doing.
I have not considered the valves but that might be the next thing I check. I have run valves on 350 & 454 chevy's and one 400 cummins but never on a small engine. Do I need special tools for this or can any mechanically inclined person perform this task with some simple instruction and a tech. manual.

Thanks

Rich

 

you can do it easily, a little patience and a bit of know how which sounds like you have, a few tools, feeler guages and no problem, good luck
Al

 

I doubt the valves could be the problem, unless they were so tight that they leak. I figured it was a long shot, but maybe worth checking really quick...

Once you have the bodywork off, there's an inspection plug on the side of the motor, chrome with allen head. Pull the valve covers off, and rotate the motor via the pull starter until you have a T on the flywheel visible in the inspection window.

Check the rockers. If they have play then the piston is Top Dead Center between compression and power stroke, and you are ready to adjust the valves. If both rockers are tight, then the valves are in overlap at TDC between exhaust and intake strokes, and you will need to rotate the motor another turn to get back to TDC with play in the rockers.

0.006 intake and 0.009 exhaust, engine cold.

 

PS Did you pull the fuel screen out of the tank? Also, I think TIC was suggesting checking the carb vent lines, which is a good idea.

 

I did take the fuel tank off and cleaned the fuel screen and the tank, they did not look bad or clogged. I have checked the vent tubes on the carb. and they are clear. I have had alot of honda engines over the years and this is the first one that has ever given any trouble.

Is there a way to adjust the fuel mixture? Could it be getting hot and loosing power do to a lean fuel mixture?

I plan on adding the toggle switch for the fan, did not know that was a popular mod. but I can see the advantage of it in trying to keep the engine cool and not letting it get hot then trying to cool it down which may be more difficult to do once it is already hot.