GXV140 Overheating

I have a HR215 K1 HXA that I bought used last summer. I've serviced it up with new oil, filter, spark and carb. It runs great but in the last month has started overheating and I don't know why. Engaging blade is smooth and doesn't dies. Any suggestions? It will mow great for about a half hour and then loose power and slowly die. Smoke comes out of the dipstick. I've pulled the carb and it's as clean as can be, air filter looks good and I dumped the oil and put in fresh. Oil level is good. I'm not sure what next. Blade clutch? Ignition coil? Thanks.

A few possibilities that come to mind.

Mouse nest blocking air flow.
Operating at less than full throttle
Air fuel mixture too lean

KC_kid said:

I have a HR215 K1 HXA that I bought used last summer. I've serviced it up with new oil, filter, spark and carb. It runs great but in the last month has started overheating and I don't know why. Engaging blade is smooth and doesn't dies. Any suggestions? It will mow great for about a half hour and then loose power and slowly die. Smoke comes out of the dipstick. I've pulled the carb and it's as clean as can be, air filter looks good and I dumped the oil and put in fresh. Oil level is good. I'm not sure what next. Blade clutch? Ignition coil? Thanks.

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When engine looses power and dies, try a spark test. If no spark, replace plug, test coil, cap and wire. Replace as needed.
If spark is good:

Dump old fuel (old fuel = fuel more than 30 days old)
Flush fuel tank with solvent
Drain, disassemble, and clean (or just replace) carburetor and all gaskets (fyi, list price on a new carb is $42)
Replace spark plug
Don't always trust your eyes on a pleated air filter. If it even looks a bit old or dirty, it's cheap to replace
Ensure all links, rods, springs, etc. on carburetor and governor are correctly fitted
Fill with fresh fuel ONLY

Does the engine smoke at all when running? What color is the smoke coming from the dipstick filler hole?
White smoke from exhaust = burning oil
Black smoke from exhaust = rich (too much fuel/too little air) fuel condition (clogged carb or air filter, stuck choke)

Vapor lock may happen in really hot conditions (fuel boils) but that's rare. Will the engine always fire back up after cooling down?

May need to use a compression tester and check engine compression, consider having valves inspected and adjusted.

With compression, spark, fuel & air, engine will run.

A shop manual can be a huge help when doing repairs; Honda sells paper copies on eBay and Amazon:

Honda Power Equipment Shop Manuals on eBay
Honda Power Equipment Shop Manuals on Amazon

Wow Robert, thanks for the thorough response, I really appreciate that.
Fuel is good, carb is good, air filter was new at beginning of season and has not been in dusty conditions - we've had a lot of moisture this year. Spark Plug was new at beginning of season too, although one time that it died I checked for spark and didn't see any. I thought maybe I couldn't see it very well because it was in direct sun - I just touched the plug to the block, pulled the cord and looked for spark. But, a few minutes later it fired right up.

It always fires up after a period of time and truly does sound/run good. Engine does not smoke from exhaust while running, only from top of engine and dipstick tube when it's overheated and after if dies. I don't think it's vapor locking either. I need to buy a manual and I don't have a compression tester. After I replace the ignition coil and make sure my RPMs are inline, if it is still happening then I'll have to look at compression and valves.

I will respond with what happens, ignition coil and tach should be here first of next week.

KC_kid said:

After I replace the ignition coil and make sure my RPMs are inline, if it is still happening then I'll have to look at compression and valves.

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I'd hold off on buying a coil unless you don't have any spark at all. It's rare for a coil to fail, but if you don't have spark, be sure the cap is okay and the plug is clean. Might want to also make sure the coil air gap (between the coil and flywheel) is okay, and the mounting bolts are not loose or the coil can be moved.

Low compression or out-of-adjustment valves are unlikely too. Low compression would probably be due to worn piston rings, and your mower would for sure smoke a bit. Valves rarely get out of spec, and you'd have backfiring or other problems. Not running when hot or cold is rarely due to out-of-spec valves.

I'd bet the problem is choke/carb or air flow related, assuming all the other rods, springs, etc. are correctly installed.

robert@honda said:

I'd hold off on buying a coil unless you don't have any spark at all. It's rare for a coil to fail, but if you don't have spark, be sure the cap is okay and the plug is clean. Might want to also make sure the coil air gap (between the coil and flywheel) is okay, and the mounting bolts are not loose

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Well I already bought the coil and it came in yesterday, but I'm out if town this weekend. A lot of small engine reading pointed me to coils going bad can cause overheating, I don't really know.
I'll respond when I get a chance to replace it and mow again next week.

KC_kid said:

Well I already bought the coil and it came in yesterday, but I'm out if town this weekend. A lot of small engine reading pointed me to coils going bad can cause overheating, I don't really know.
I'll respond when I get a chance to replace it and mow again next week.

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KC, It's overheating can cause the coil to go bad. Seeing a spark is no guarantee coil works at hot. Don't shops have a coil tester?

motoman said:

KC, It's overheating can cause the coil to go bad. Seeing a spark is no guarantee coil works at hot. Don't shops have a coil tester?

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I was trying to avoid a shop charge. So your saying the coil may stop from the overheat but not be the cause of it to overheat? Hope I figure it out soon. Seems like am engine like this would be easy to diagnose.

Have you checked the muffler to see if its clogged or restricted?

BlazNT said:

Have you checked the muffler to see if its clogged or restricted?

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No, I have not. I will make sure and do that when I'm working on it. Clean muffler, replace electrical, double check clean cooling fins, check RPMs and throttle linkage. Might get a new air filter although I hate to replace a filter I am 90% sure is clean. I know carb, oil and gas are clean. Engine acted exact same with 2 separate clean carbs and fresh oil. Running 89 octane gas.