Cub Cadet 1330 Starting Problems

[mbrenner]

Need help figuring this one out and figured you all would know best. I am having trouble getting my 1330 (Kohler Command 12.5) to start. I have been mowing with it for a few weeks so I know it can run perfect, I put a new oil filter and air filter on it at the beginning of the season and just changed the plug Saturday when I couldn't get it going. It seems to be getting fuel (double checked the fuel filter) and spark. The last two times I mowed it was also hard to start but did fire up. I will sort of half-fire for maybe 6 or 10 times. Like it is missing every other spark. Before it would rev up to normal idle and I would have no problems the rest of the day (starts fine when warm). Now even if it does the half-fire it wont catch up. Sorry for the long explanation but I am running out of ideas. Thanks in advance!

 

[jdiederichs]

Matthew,

You may want to borrow a spark tester to see if the igntion module is failing, but I suspect that you have a partially sheared flywheel key. In other words, the key may be in one piece yet but indented deeply that throws off timing. I have seen plenty of those on Kohlers like yours.

You will have to
A) have a qualified dealer check it, or
B) remove the top engine shroud to gain access and pull the flywheel to check the key. Can't tell by looking down the keyway, you actually must remove the flywheel to inspect the key.

What often causes these keys to fail is a backfire on shutdown; these can be avoided by shutting off the engine at 3/4 - full throttle if you have a fuel solenoid on the carb (look for the red wire at the bottom of the fuel bowl)

That procedure (3/4-full) will prevent backfires as the main jet is closed when the key is shut off, so no raw gas is drawn into the engine and ignited in the muffler. The throttle plate is open at that throttle setting so no gas is drawn in through the idle jet either = no loud bang!

 

[jdiederichs]

PS, always install a new key and torque flywheel to 49 ft/lbs. I run for 30 sec and retorque as this "seats" the flywheel to shaft.

 

[mbrenner]

Thanks for your input. If I have a good blue spark do you think I would still need to get ahold of a tester? It seems plenty stong to me.

 

[jdiederichs]

Nah, just r&r the flywheel, replace key. Sure sounds like dozens of cases I've seen.

 

[mbrenner]

Thanks. I stated into it when I got home and had a few quick question. Since I dont have a service manual, what is the correct way to hold the flyweel when you loosen/tighten the bolt? In most other applications I would expect to put a punch through one of the two holes in the flywheel to keep it from turning? Is this the proper procedure? It almost looks like there could be a spanner wrench made for this flywheel. The second thing is, I would assume I need a puller to get it off? Since it is a steel flywheel and not aluminium, can I just pull on the ring gear? Thanks again for the help!

 

[jdiederichs]

You may find a spot to wedge a large screwdriver against the ring gear (such as by the starter). Do NOT use the ign. module towers, they will break off easily, then you'd be outa luck.

The bolt generally is not very tight. That part will go easily. The use a steering wheel puller or similar to pull the flywheel. You'll need 8mm.capscrews to thread into the tapped holes in the flywheel. Do not attempt to use a multi-jaw puller over the ring gear, if you don't have a steering wheel puller many auto parts stores sell/rent them.

 

[mbrenner]

Well, I pulled the flywheel tonight, the key looked fine but I replaced it to be sure. No change. I tested the magneto as they istructed in the manual, it had 14,000 Ohms resistance which is what it should. So I have spark, I have fuel, what else could it be? I put my finger in the sparkplug hole and there is compression. It doesnt even want to fire with starter fluid. Any ideas?

 

[jdiederichs]

Sorry, but based on your description I'd have sworn it was a key!

That's the most common problem.

Next I'd pull the valve cover and watch the valve train operate. May have an intake valve push rod bend or dislodged; not opening.

Since these engines use hydraulic lifters they are very oil sensitive; the manual insists on using 10W30 oil only. The reason for this is that the hydraulic lifters must "pump up"&"bleed down" just like in a car, (they are, after all Chevy-style lifters) so oil viscosity is key.

So taking a peek under the valve cover is where I'd go next...might see a rocker arm bolt loose or stuck valve or bent/dislodged push rod

 

[mbrenner]

Maybe I misjudged the spark strength. Would a magneto on its way out give good spark when the engine was running, and also when starting warm but have problems starting cold? Warm combustion chamber = less heat required from spark?

 

[jdiederichs]

Typically the reverse is true, a module will be at it's strongest when cold, as it heats up it'll malfunction and fail to fire. Did you reset the gap after you reinstalled the flywheel? That's critical, shoot for a .012" gap + 0r - .002.

 

[kweaver]

Does it have a condensor ?
Are you testing the spark with a plug tester or a spark plug ?

 

[mbrenner]

I did not check/reset the gap, I will try that tonight. I do not have a condensor. The plug wire runs right from the magneto to the plug. And I did not use a spark tester, just a plug.

 

[kweaver]

I was just wondering. I use to buy any old engine that I'd see along the road or flea market. I found out that a plug tester light will "show" good but they wouldn't fire a plug. I then found that if they tested good but didn't fire it was because the condensor was shot or weak.

 

[jdiederichs]

Matthew I would try to hold the gap around .011"; slightly loosen the module mounting screws, bring the flywheel magnet around to line up and adjust the gap. Turn the engine over by hand 1st so you are sure the f/wheel doesn't hit the module in it's rotation.

 

[mbrenner]

How sensitive is the valvetrain really to the oil? Would it be worth changing the oil just to eliminate that possibility?

 

[dross]

Kentucky, My spark tester makes the spark jump a gap about 3/8 (mabey half) an inch. would a bad condenser jump that?

 

[kweaver]

Dave - I wouldn't think so. That's a heck of a gap to jump. The cheap light bulb type aren't trustworthy , which is what I've got. I've also got a spark plug with an alligator clip and wire soldered to the plug's ground.

 

[jdiederichs]

Matthew,
The simple answer is "NO" simply switching engine oil is not going to correct what happened.

You still need to R&R the valve cover and inspect the valve train or (going back to my original reply): Have a qualified dealer }check it