1450- New to me, won't start. Pulling my hair out!
 

I bought a 1450 this weekend. It was 2 1/2 hours away, but a decent deal and I've been wanting/needing something with a hydraulic lift (for tiller, blade, etc..) for a long time.

I get to the place and find out the guy is a recently retired International dealer, had rebuilt and over-bored the engine himself. It supposedly had about an hour of run time since rebuild. I drove the tractor around a bit, felt real good about the deal, loaded it, blade and snow blower on trailer, and happily brought it all home.

At home, I use the tractor to pull the blade and blower off the trailer and to the barn, put the deck back on, fire it up again, start the deck up, it mows about 10', it bogs down, backfires a couple times, and dies. I start it again, start the deck, same thing, bogs down, backfires, and dies. Start again, try to make it to my shop, backfires multiple times over about 20', dies, never made it to the shop, wont start at all now.

I pulled the side panels and air cleaner off, notice immediately that the carb is spitting gas while I turn it over. I remove the carb, take it to the bench, disassemble, nothing noticeably wrong, give it a good cleaning, make a slight adjustment to the float, factory set the needles, and put it back on.

Now there's no spitting gas, and after a few unsuccessful attempts to start, there's a fine fog of fuel fumes in the intake.

Here's a list of what I've done the last couple of days (In no particular order):
Checked for spark by laying plug on engine and cranking over (multiple times, and after every major change).
Ensured there was no arc at the points (multiple times).
Set and checked the timing by static timing method (checked multiple times).
Ensured 12v running to coil with key on.
Tested coil resistance (good).
Installed known to work coil from my 680.
Tested for continuity of spark plug wire (had some resistance, replaced with good wire).
Installed known to work condenser.
Watched through intake port and spark plug hole to ensure valves are moving correctly (they seem to be).

No matter what I've done, I get the same scenario. Engine cranks just fine, sometimes sounds like it's firing, sometimes puffs a little white smoke from the exhaust, has a fine fog of fuel in the intake, with no excess fuel build up that I can see, but still won't start at all.

I'm already admitting that I've been had by this supposed expert. But I took the deal, so I'll deal with it.

I don't know a lot about these engines, but I know enough about engines in general to guess that it's boiled down to a compression issue.

What's next? Do I need to tear apart this fresh, dealer rebuilt engine? Start with the valves then check the piston rings? Or is there something obvious, external, that I'm missing?

I own 5 Kohler K series engines, and I've never had this problem, and never had to do any internal engine work.

Thank you in advance, any input will be greatly appreciated.

Something simple if you haven't already, try changing spark plug, I've had engines that won't even start, maybe pop every once in a while, but no start. Then when I change it it runs like its brand new. Something to try. Even if the plug looks good, doesn't mean there might not be something wrong with it.

I did not read that you replaced the spark plug. It could be fouled after the backfire issue. Seems like whenever I have backfire issue, I adjust or rebuild the carb, always replace the plug and they fire up for me. I would replace the plug with a new one and try again.

Cub Cadet 123

pull the line off the carb and make sure its flowing properly

Ya plugs can do the most silliest things. It can go from not letting an engine run good, to not even being able to start. And its something so simple, everyone just goes over it without changing it. I've done it before. Even if the plug looks good, change it anyway. Knock off one more variable.

Thanks for the quick responses, I have not changed the plug. The one on there has no fouling, and produces a nice bright spark, so even though I changed a few working parts, I overlooked changing the plug. I don't have a new one on hand and live 25 miles from the nearest town, but I'll check in the morning and see if the same plug is in the 680 (that runs fine) and try that.

Olds45512- Yes I checked fuel flow. Getting nice clean fuel from the line, and after cleaning carb blew through all holes to ensure they were open as should be.

I have not seen you post for a while sg. porter. Good to hear from you again!

Cub Cadet 123

Thank you! It has been awhile. It's a long story about shattering my spine and becoming disabled that doesn't really belong in this thread, but yes, it's good to be back around, and able to do a little playing with my cubs!

Well that does not sound like fun! Been dealing with back problems my self and it p*sses me off the most when i cant take a ride across the yard on one of my stiff riding cubs without being laid up for a week. Good luck to ya with the back situation.
Have you done comp. test? When i do a rebuild I will run engine for a while to get nice and warm and retorque head. i did a rebuild on a buddys shovel head last year and he did not bring it back after he took off with it, end of last years riding season here in up-state ny, and his first ride this spring he blew out brand new gasket after just 100 miles.

Check your valve adjustments.

Sounds like everything else is in order. From the description, I'd say valve issues.

Bad or incorrect fuel? Water in fuel?

Same spark plug in the 680, no change in condition or symptoms.

Nope, I drained the gas tank the first time I pulled the carb just to eliminate that possibility. There wasn't much fuel in there.

This is what I'm thinking/hoping. I read up last night on valve adjustments and engine disassembly. If I get lucky I won't have to go that far.
I have the feeler gauges I need, but I also got a honey-do list for my wife's business today. She's got a big event this weekend, so the 1450 will have to sit till next week.

Will update again when I figure something out or fail...

Ok. If i read your post correctly, you said that it was running but bogged down and died and not will not restart. Im going to go for a blown head gasket or the head has a build up of carbon. I had the same problem with one of my QLs.

Id try pulling head, cleaning it and double checking head gasket.

Hope you fix your problem.

John

I'm sticking with valve issue...

Wanna bet? :biggrin2:

Torque back the head and adjust the valves clearance first as indicate in Kohler service manual (Section3 page5).If this not solve your problem collect Jonathan, I agree with his statement but it's his bet :biggrin2:

These "remote diagnostic" exercises are always interesting. So I've been following the discussion. I usually side with Jonathan on these, based on his extensive experience (and he's usually correct) but I'm curious what about the symptoms points to valves?

The tractor ran, then something changed and now it won't run. It backfires, so that sounds like timing or valve problem. Is it "backfiring" out the carb or is it "backfiring" out the muffler?

How could the valves go out of adjustment all of a sudden? so much so that now it won't start.

Blown head gasket shouldn't cause it to not start (usually) and doesn't account for the backfiring.

To me, it's unlikely the valves went out of adjustment. All of a sudden. I guess they could start sticking all of a sudden, so that's a possibility, but the OP watched them operate, and they seemed to be OK.

I'm thinking it's a timing issue. Since there is good spark, I'd be double checking the static timing to be sure it hasn't changed. timing can go out of adjustment if the points are loose...you'd still get spark, it would/could backfire, but probably would not start if off enough.

That's my vote. (sorry, Johathan).

Can it be a stupid thing like the carburetor no sitting well anymore on the intake? This engine run only 1hr and since the OP is not the guy who rebuilt this engine, I think a meticulous inspection need to be done step by step.

My swag is compression loss. Chunk of crud under an intake valve? There is a reason gas is spitting back into the induction system. Valve or timing. BTW, backfire is through the induction system and after fire is through the exhaust.

I remember working on a fresh rebuilt air cooled single cylinder motorcycle engine for a guy and the engine start and run perfectly until he reach his running temp then he start to backfire and finally he die. I check the timing , the valves the head gasket, nothing was wrong. I never found out what was really the problem but after I torque back the intake tubing and the carb he run perfectly well....Go figure. :bash2:

I just got home for the evening and, as stated, wont be home to even look at it again till Mon. But it's bugging the crap out of me every minute.

I mentioned the tractor was backfiring, but it was actually afterfiring. It was spitting gas out the carb and backfiring in the exhaust. I know the difference, it's just so much more natural to type backfire for some reason.

As for the static timing, I checked several times, I checked everything after changing anything. After the initial cleaning the points and slight adjustment, the timing never changed throughout the process.

One way or another, it has to be a compression issue. The fuel is now as it should be, the spark is now as it should be, the only missing major component of an old engine is compression.

Without breaking into it yet, I'm agreeing with the valve issue, whether out of adjustment, or not closing. The occasional puffs of white smoke and sometimes sounding like it might have fired, makes me think it's burning uncompressed fuel.
After having to adjust the carb, replace a less than great spark plug wire, and the issue in general, it's not going to surprise me if at this point I open up the engine and find out it wasn't in the condition he claimed it to be or he wasn't as good as he claimed to be, and I'm going to find a foreign object like a nut or snap ring jammed in the exhaust valve preventing it from closing.

That type of situation would explain the sudden change. I had something similar happen in a fresh rebuilt chainsaw once. Chunk of the old spark arrester sucked back in through the exhaust port and killed it. Tried and tried and tried to start it with no luck, opened it up all too late to find the piece had dislodged from the exhaust valve and destroyed the cylinder wall through multiple starting attempts. That's why I'm kind of leery (other than I just know better) of turning the engine over any more than I had to for diagnosing the problem.

You all got a few days to get your bets with Jonathan on the table... Lol
And I will get pictures up when I see my tractor in daylight again.

Feeling your pain
 

Your last post got me thinking, you may want to make sure you re not missing any air cleaner or butterfly plate screws, Just a thought to go with the statement of finding something in the combustion chamber.

I understand the statement of bugging you every minute. These little beast seem to do that to you when somethings not right with them.

Can't give away all the secrets before the bets are made! :biggrin2::biggrin2:


You are right about timing though Frank. It is possible.

I'm sticking with valve issue.
(Just so it's clear, that's a non-specific claim..... ANY issue found with valves is my bet. Not just "out of adjustment"...)

Not knowing just asking.
Does that engine have an "Automatic Compression Release"?

Yes. :beerchug:

I think since the stakes on this bet are so high I'm going to ask for more than just valves.:biggrin2:
Since it was just rebuilt I'm going with not enough stem to guide clearance, maybe the reamer they use had reamed too many guides and was worn.
It's just a guess though. And I'm usually wrong!

You play it safe...:biggrin2:

This included the valves, valves seat, valves guide, valves spring and even the small levers on the camshaft that trip open the exhaust valve at low turning speeds to reduce compression.

Smart bet:beerchug:

:biggrin2::biggrin2::biggrin2::beerchug:



So far I'm the only one who says valves, so we'll see if I'm right.

Yup. Valves it is. :BB&YS:

Had a little time to poke around the cub this evening. My feeler gauges went AWOL, (I have 3 boys and share property with grandpa, common problem), but I don't need them to see what's going on.
Basically, the exhaust valve is slightly opening during the compression stroke!
Watching the valves and the piston (through the peep hole) with breather removed, turning engine clockwise (from drivers seat):
1. Intake valve opens as piston moves downward (aka intake stroke)
2. Piston moves upward (aka compression stroke) but about halfway through the stroke, the tappet presses on the exhaust valve, slightly opening it (observed at tappet and through spark plug hole)
3. Power stroke seems normal
4. Exhaust stroke seems normal

I'm not an engine expert, but I'm pretty sure it's not supposed to work like that. As stated, the engine acts like there's no compression, now I can see that is exactly the case.
I took video, but no idea where to put it or how to post it.

So, what's next?
1. Is it common (or not so common) to have a cam (Lifter? Roller? I have not got that far in studying these engines...) slightly out of round, and a proper valve adjustment will compensate for the difference?

2. Should I stop messing with it, stop turning the engine, learn how to tear down and rebuild and then do it before I screw something up?

Still irked about the whole situation. It would be one thing if I bought the cub from Joe Shmoe with a yard sale sign, but this came from an IH Dealer/Family, I drove it out of a barn full of cubs (talked with the owner about making a future offer on a broke down 108 shoved in a back corner), one of the guys ran back to the dealer shop to grab the 4" binder full of every manual I could want, I spoke with the guy who had just rebuilt the engine, claimed he'd done it for the shop all his life. I never imagined I was driving 2 1/2 hours and paying good money for a cub that would blow up 10 min after I got home...

In other news, blew a pretty bad oil leak in the 680 while mowing today. It was too hot to mess with so I haven't even pulled the engine shrouds off to see where it's coming from.
Apparently, my comment about 5 K series engines and never having to do any internal engine work is coming back to haunt me...

Why does that feel like deja-vu?:biggrin2:

http://www.onlycubcadets.net/forum/s...ad.php?t=36455

Read posts 5 and 6.

Well dang it, I thought I was on to something.

thats normal, the engine has a compression release to help it start.

Thanks for the info. I read up on the compression release (new to me) and managed to track down my feeler gauges. The intake valve is set to .009" clearance and the exhaust is set to .019", both within spec.
As soon as I can get to it, I'll pull the engine shrouds and check the head bolt torque.

Just go ahead and pull the head.

Have you tried starting it with some starting fluid? Just a thought before you pull the head..might reveal a fuel issue... and double check the spark is good.

I'm still betting it's NOT the valves...Beginning to feel better about my bet now...

I'm not convinced.

If not a valve problem, how is the gas spray getting back into the intake? :bigthink:Personally, I would be a bit hesitant to personally bad mouth the seller 'till I knew exactly what the problem actually is. Sh_t sometimes happens.

Have you done comp test?

Engine has a compression release. Not simple to do a compression test. Easier to pull the head and look.

Just for S and giggles i just tested the compression on one of my 1650's.
30# after 3 hits on the gauge, wide open throttle. The tractor has been sitting for about a weak and it's about 60* in the shop.
This tractor will lite right off any time.
For what it's worth