How hot is too hot?

red211 · #1 04-24-2011, 06:53 PM

OK, how hot do your cubs run when mowing? The carb on mine is so hot you can barely touch it after running for a while. I got halfway through the back yard when it started running bad again and just wondering if I'm maybe chasing the wrong problem. I have not pulled the bowl off to check for crud again, but it will run at half throttle, but above that and it bogs and will die. I did notice that the other day when I had the bowl off while hot, I turned the fuel on to flush the line and it would just spit gas out the seat with the needle out, not a steady flow, but had a steady flow out of the line when removed from carb. No trash in seat, I had blown it out before. Is this normal or is it getting too hot and boiling the fuel in the bowl? The air coming out of the holes for the head bolt access doesn't seem too hot but the air coming out the front is HOT, course it is passing the muffler so it should be hot. There is no glow in muffler that I can see and it doesn't really smell hot, so am letting it cool without carb work. If it won't run when cooled I know it is trash in carb and the extra heat could be from lean condition after main stopped up. So, how hot should the carb be?

_DX3_ · #2 04-24-2011, 07:29 PM

Is there a thick spacer (1/4" or so) between the carb and engine? These help keep the carb cool and from over heating..

R Bedell · #3 04-24-2011, 07:29 PM

If this were mine, I would pull the Motor Shroud (Tin) and make sure there is no debris in the cooling fins and/or the flywheel fan, and there is good air movement.

red211 · #4 04-24-2011, 08:03 PM

Quote:

Originally Posted by _DX3_

Is there a thick spacer (1/4" or so) between the carb and engine? These help keep the carb cool and from over heating..

Don't think there is a spacer but will go down and check, will carb overheat without it?

I wondered about the air flow but it seems good out of the head bolt holes, I put a head gskt on and had the top cover off. Didn't see anything that would cause air flow trouble, but didn't remove the fan cover and inspect fan.

What does it run like if to hot, does it shut off? Mine just won't pull past half throttle, any load makes it bog and try to die, but idle and low throttle it runs fine. Every time I pull the bowl it has had rust that looks like mud.

ljones · #5 04-25-2011, 08:00 AM

A carb spacer would not be oem so if you did not put one on it proably is not there.

red211 · #6 04-25-2011, 08:45 PM

Now I am starting to think maybe the coil is going bad. Ran good for 15 minutes than I ran the tank dry darn it. Put some fuel in and it still ran ok, but was sounding a little weak. Just as I finished up it started acting up, maybe 20-25 minutes with the fuel stop. The points, plug and condensor are new so I would be leaning toward the coil. Anyone had this type of simptom from a coil?

fisherman1526 · #7 04-26-2011, 10:55 PM

I have, in fact sounds like the same problem. Almost like the timing was off, so i'd play with it, put new points in and play some more. It got very irritating. Then for whatever reason I switched the coil and it has been fine since. I never thought it was a bad coil because it was brand new from napa, so much for that idea.

red211 · #8 04-27-2011, 07:51 AM

Quote:

Originally Posted by fisherman1526

I have, in fact sounds like the same problem. Almost like the timing was off, so i'd play with it, put new points in and play some more. It got very irritating. Then for whatever reason I switched the coil and it has been fine since. I never thought it was a bad coil because it was brand new from napa, so much for that idea.

That makes it tough to find when a new part is bad. Your sure it issomething else cause you just replaced it. Some problems are hard enough to narrow down without new stuff going bad. I will be trying the coil if it quites raining long enough to get it out and mow for 20 nimutes or so. I ohmed both my coils and the readings were close so not sure, after getting hot the one on it could be breaking down. Will have the other handy next time to try

JOHN SCHUTTE · #9 04-27-2011, 09:09 AM

Red211, other than the coil, I would check the fitting in the bottom of the fuel tank for a blockage. I have seen a rust flake blockage at that point and act exactly like a coil breaking down.

red211 · #10 04-27-2011, 09:11 AM

Quote:

Originally Posted by JOHN SCHUTTE

Red211, other than the coil, I would check the fitting in the bottom of the fuel tank for a blockage. I have seen a rust flake blockage at that point and act exactly like a coil breaking down.

Will do, thanks!