Outdoor Power Equipment and Small Engines - 9HP John Deere rider won't start backfire thru carb

I have a 9HP John Deere rider that I inherited from a buddy that moved to Canada. It sat for about 3 years in a storage building before I got it. It wouldn't start at first, so I did a carb tear-down (I've done a number of Quadra-jets and motorcycle carbs, so this was a cake) and slapped it back on. Started right up and ran all last summer and fall. Since we live in the South, it's been run a few times over the winter (kids hauling leaves and branches). Now the thing won't start. I pulled the carby and it looks fine. Plug I cleaned up (not that it was that bad). Tried starter fluid, no luck. It cranks and cranks all day, but mostly it just backfires through the carb. I was going to tear the dumb thing apart and check the valves, but that's quite a job, so I figured I'd ask for some advice. What's the path of least resistance? Are there some simple things to check first? I have no idea how to check timing on a lawn mower (I hooked up the gun and spent an hour looking for somewhere to point it -- just kidding).

Thanks for your consideration,

Bob in SC (where the grass grows fast) :wall:

You could give the flywheel key a check, not to hard to see if it isn't the problem.

on my 8hp jd I had this but on the exaust. I think the valve stuck but it finally freed up on its own. Try and spin the engine by hand, if a valve is stuck open then you will have no compression and it will turn easily. While you turn it you should have resistance on every other stroke.

What engine do you have? A kawasaki? Is it a little mower, like an RX95? If so, I would suspect the igniter pretty quick from your description of the symptoms, but reply with engine brand and we'll go from there.

9HP Kawasaki OHV on the little rider (SX75). Engine Code FC290V AS02.

One other thing, there's a spring-loaded lever on the block that hooked to the throttle linkage. It doesn't appear to move any when you move the throttle lever, but it's the only thing hooked to the throttle plate. If I hold that lever all the way to the left (against the spring), it will not backfire and will start for a second or two and then die. I guess this is some sort of govenor or something?

That lever is working properly from what you've said so far. It only pulls back when the engine gets started. The governor controls it. Have you tried a new spark plug?

I've run into this problem on that engine a few times. There are 2 reasons most of the time. One is the valve clearances being too small, and the other is the igniter. There is no test procedure for the igniter, so check the valve clearances first (after trying a new plug).

Not likely the flywheel key. Ideally, you want to check the ignition strength with an inline tester, the spark plug on the head trick is sometimes false. I'd do this before tearing into the valve train. These Kawi igniter modules are to blame most of the time. BTW, the module is about 3/4" square located near the speed controls on the carburetor with a single wire coming from it.

I guess I'm off to get a plug and start researching where to get the ignitor. The engine is discontinued, but hopefully parts are still around.

By inline plug line tester do you mean the inductive fluorescent pickup type? I tested it with the engine block test before.

Bob V

:madhell: start baby . . . start!

The tester you're referring to is an automotive type and ideally you'd like to use a small engine type. Briggs, Tecumseh and Kohler all have one available, check with your local small engine shop to get one (two, if you ever intend on checking a twin cylinder small engine out).

Any Deere dealer should have the igniter. I would suggest making double sure that the igniter you get is original equipment for Kawasaki. The deere dealer in my area has sold me igniters packaged by deere, and supplied to them from an aftermarket dealer. I don't think I ever had one of them last over 6 months. An original kawasaki igniter normally lasts a decade or more.

it's the plug trust me

Cheese, is there a way to distinguish an aftermarket igniter from an OEM? I've never paid close attention when installing a new one...just assumed!

Usually the OEM ones have some kind of black ink trademark emblem stamped on them. I just get the ones in Kawasaki packaging instead of the ones offered by Deere in Deere packaging. I don't know if anyone else offers aftermarket igniters or not. The OEM ones cost more too.

A compression check would help.The former owner may have gotten starting fluid happy and bent a valve.

My money is on valve trane, Overhead valve could have a number of problems leading to result. Brocken rocker, stripped stud, push rod came out when valve possibly stuck. I have seen plenty of plugs cause same problem and if flat head might agree but OHV, gotta be valve rocker issue.

This thread is over a year old...;)