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TommyK

BAM! No, not Emeril

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TommyK

I've had a 5212.5, my 'Deuce', for a couple of summers. When she runs, she runs like a top.

However... the Deuce has two problems.

A. Hard starting. Starter motor spins the crank shaft like crazy, but no fire. Usually, I stand up and lean forward on the running boards, then twist the spark plug cables, which usually lets her fire right up. Sometimes, a little more cranking is in order. So, I'm not sure twisting the spark connectors is doing the trick. The plugs are new and the threaded finials on top are tight. I replaced the cheapo B/S spark plug connectors on the spark wires with more secure automotive type connectors with the intent of ablating the problem. No dice. She will still fire up, but only with some coaxing.

B. When I shut her down, I get a loud backfire, 8 times out of 10. This usually follows 5 - 10 seconds after the crankshaft has come to a complete halt.

I have tried revving the motor up to WOT, then killing the ignition.

I've tried throttling down to idle for 20 or more seconds, then killing the ignition. Nothing seems to help.

Are these problems related?

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JohnMBerst

Interesting my 5212.5 does some of the same.

The back fire I found was due to not shutting down as the manual suggests. Now I let it idle for a few seconds at just over half speed and turn the key off. The carburetor has a solenoid with a plunger to shut off the gas flow. For 20 years doing it wrong, the last 2-3 right has solved that problem.

Compaired to my 6216 the 5212.5 takes longer and a bit harder to start. Not sure of the cause, but plug and gas is good, and carb is clean. Battery is strong. I have more of a problem when warm, which is a real bugger. Hoping to take the heads off for the first time this winter and clean. Should be intersting to see what 2200+ hours look like.

Look forward to seeing others input.

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TommyK
Originally posted by JohnMBerst

Interesting my 5212.5 does some of the same.The back fire I found was due to not shutting down as the manual suggests. Now I let it idle for a few seconds at just over half speed and turn the key off. The carburetor has a solenoid with a plunger to shut off the gas flow. For 20 years doing it wrong, the last 2-3 right has solved that problem.Compaired to my 6216 the 5212.5 takes longer and a bit harder to start. Not sure of the cause, but plug and gas is good, and carb is clean. Battery is strong. I have more of a problem when warm, which is a real bugger. Hoping to take the heads off for the first time this winter and clean. Should be intersting to see what 2200+ hours look like.Look forward to seeing others input.

id="quote">Oh goody! :D I get to re-build the carb!. This should be interesting.Any idea how to find determine whether the solenoid is functioning properly?

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BLT

You should be able see the solenoid from the RH side when facing the the hood grill. By turning the ignition key to run and off you should be able to both feel and hear clicking. That's an indication the solenoid works.

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TommyK

Bought a new solenoid valve, $98.50!!!!

The old one? The tip was 'machined' to a some-what rought wedge. i.e. some nimblewill previous owner appears to have clipped off the end with a side cutters?!?!

New shut-down procedure: Throttle up to WOT, hit the kill switch. As the engine spools down, after the valve closes, the remainder of the fuel passed the valve gets burned up in the usual way... no back fire.

Problem. I trust my local dealership implicitly, but I decided to check price and availability anyways. A quick 'net search came up "Obsolete, no replacement" on 3 different parts sites. One site's preview showed a comparable price, but when the page opened, it was unobtainium.

The solenoid valve in question: part number 1640904 which crosses to 397266.

Anyone got a suggestion should I need another solenoid? I'll be darned if I know where my dealer got his, but it was on the shelf and looked to be fairly recently made; no oxidation on the metal case. This is why I trust my dealership, he usually comes through in a clutch.

There were a couple versions of the shut-down solenoid. Also, the carb. drawing show an optional, manual (screw driver) needle valve in place of the fuel solenoid. Can these be retro-fit?

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TommyK

Additional information on the spark plug issue:

The old plugs (when I acquired her used) were the Walmutts variety, shorty short lawn mower plugs. I used the spark plug identification manual at Farm and Fleet to select the correct ones with longer threads. I threaded the washered plugs into their proper holes using my arm-a-matic torque wrench (by guess and by golly) to install. They seemed to have bottomed out. Due to the shrouding, I couldn't see that the washers weren't properly seated.

After removing the heads, I realized that they were threaded in no where near deep enough. A bit of clean up from ignition fouling on the deeper threads due to the too-short plugs installed by the P.O. helped get the new, correct, plugs fully seated.

Basically, the spark was firing way up inside the threaded port instead of in the combustion chamber.

The P.O. is probably the same P.O. who "customized" the fuel solenoid.

sm00

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