Lawn Mower Spark Plug Burning Hot

[Skoot]

First, I know this is not boat related and I searched Google over and over and could not find an answer.  Soooo, I figured I'd turn to the Aqua-net for an educated response.  Thanks in advance.

Is it normal for 6.5hp Tecumseh engine's Spark plug to be burning hot after 1-2min run time? The entire plug was burning hot, enough to sizzle a drop of water when applied to the hex nut down.

[fitz73222]

Hey Scott,

1) Lean; leaky intake to carb gasket, partial plugged main jet. Is it hard to start and does it surge?
2) Not sure what plug to use but CJ-8 or J17-LM comes to mind.
3) Least likely; intake or exhaust valve not seating correctly and the valves are overheating because they can't transfer heat back to the cylinder head.

[Skoot]

1. Yes, I've had to over priming it lately to get it started (8-10 primer pumps)  and yes it surges
2. Your absolutely right, CJ-8 - (Just did a tune-up hoping that would fix the issues)

Also when I pulled the old plug the Grounded electrode was ash white

[fitz73222]

Probably some varnish in the float bowl and plugging the high speed nozzle. Take the carb off remove the bowl, remove the float pin, float and needle valve and soak in parts cleaner for 20 minutes. Most of the time you can take these apart without having to replace any gaskets if you are careful!

[dburr]

If you decide to blast the bowl fuel intake with the compressor for good measure, dont forget to keep you finger over the needle seat when you do... Nothing is worse then hearing, after the blast of air, "tink" as the needle seat goes zinging across the shop..  For some reason I am still learning that lesson...

[John Jones]

Most of the time you can take these apart without having to replace any gaskets if you are careful!

and don't soak the gaskets or other soft parts in carb. cleaner.  

[Skoot]

Sounds good, thanks guys!  I'll give it a try (hopefully tonight) and report back.

Thanks again.

[flounderpounder225]

Sounds good, thanks guys!  I'll give it a try (hopefully tonight) and report back.

Thanks again.

and run some heavy dosed gas with sea foam in it for the run up, it may clean up any remaining deposits, and decarbonize the cylinder head.. just my .02

[Skoot]

Thanks again for all the tips, Heres the update:

So I cleaned the carb, re-assembled, added a hefty dose of seafoam to the tank, went to pull start it and NOTHING.  I primed and primed, and still nothing.  Check for spark, with a spark plug tester and it lit up so I figured that was good. It sounds DEAD.  :evil:

I did notice (and I don't know whats its called) the cylinder part coming off the carb and curves into the engine was dirty and burnt looking.  Also where it attaches, on the inside of the engine it was very burnt looking. I ran my finger along it and it was rough and pieces of grit came out. Not sure if that's normal.

So, Im not sure what to day, I may just take it in.  :shaking2:

[fitz73222]

Hi Scott,

With what, and how did you clean the carb? Did you tear any gaskets? Is your carburetor  part of the fuel tank assembly or is it separated from the fuel tank? I'm not sure what you are describing that looks grimy and burnt. Are you talking about the head gasket joint?

[Skoot]

Hey fitz, I cleaned the carb with Spray carb cleaner, and I dont think I tore any gaskets.  I removed the bowl and float and cleaned all in there with the spary cleaner.  Here is a pic of the Carb and part in question(see yellow arrow)  Also, I forgot to mention that Hose above the Primer bulb was missing when i took the cover off.  got a piece of fuel line and replaced it.  Not sure what its for, but figured it needed to be there