Small engine hard to pull start? Small engine experts needed

[Sh40674]

I got a swisher 44" finish mower. Has a 10.5 briggs IC. Picked it up, needed some TLC. Basic maintenance and was missing the recoil starter. Got a new recoil, got it started. Hit a slightly hard wall some times when trying to start it but it was definitely never smooth pulling all the way through. It leaked some gas out of the bowl so I took that off, new gasket, got it fired up again. Went to start it an hour later and it would hit that wall REALLY hard, and also recoil back into the engine, damn near broke my fingers. Tried and it was stopping me in my tracks. Tried another pull and it broke the dogs inside the recoil so now I need a new one. Had some slight smoke coming out of the air intake/carb. When the recoil broke it yanked so hard it took the engine cover off with it. I did notice when it was running that the blades were turning slowly while it ran without the blade engaged.

1. What is the smoke from?

2. Why is it so hard to pull? Why hitting the wall and why is the recoil yanking back into the motor? I know the wrong stroke it'll be tough to pull but this stopped me in my tracks.

3. Is it maybe because the blades are engaging with the motor and im catching friction on the belts?

 

[Kaizen]

I’d definitely take the belt off and start eliminating possible issues.
Definitely pull the plugs and see if it turns over smooth. If it doesn’t take a look in cylinders.
If it was sitting who knows. Whatever you do don’t pull it hard. Could have a piece of something now jammed in there.
I have a 5hp pressure washer that runs and then if I pull hard to restart it feels like it’s locked up. If I slowly pull it over then I can pull again and it’s fine. Almost like vapor lock


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[Sh40674]

I’d definitely take the belt off and start eliminating possible issues.
Definitely pull the plugs and see if it turns over smooth. If it doesn’t take a look in cylinders.
If it was sitting who knows. Whatever you do don’t pull it hard. Could have a piece of something now jammed in there.
I have a 5hp pressure washer that runs and then if I pull hard to restart it feels like it’s locked up. If I slowly pull it over then I can pull again and it’s fine. Almost like vapor lock


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Even if I pull slow it still seems to hit that wall fairly good. Whenever I get a new recoil in the mail I'll try without the plug.

I took the flywheel cup off and it seems the flywheel key is ok. I see it in there and both slots are lined up. I cant figure out why it yanked the cord back in

 

[chuck356]

Sounds to me the carburetor is leaking fuel into the cylinder and hydro-locking the cylinder.

 

[Dustball]

Do some research on compression release.

 

[charbar]

Anywhere on the end of the crankshaft that you can get onto it with a wrench or something and try turning it over by hand?

 

[The Cobbler]

Sounds to me the carburetor is leaking fuel into the cylinder and hydro-locking the cylinder.

X2...

 

[Sh40674]

Anywhere on the end of the crankshaft that you can get onto it with a wrench or something and try turning it over by hand?

Without the plug i can spin it easy by hand on the flywheel

 

[charbar]

Spin it with the plug in. As a couple guys said, could be gas hydrolocking or possibly valve issue. You'd never notice that with the plug out though.

Any way for ignition timing to get off on it that could cause a kick back if some sorts?

 

[101SCOUT]

Pull the valve cover and spark plug. turn the engine over slowly and watch the exhaust valve rocker to see if it moves a little on compression stroke about half way to tdc. If it does not you need a cam, while your there check valve lash.
Known problem on b&s intec single cylinder engines.

 

[Jazz1]

Do some research on compression release.

X2,,,depending on age of unit..my '73 12hp briggs has compression release thing...two springs on it,,,if one of those springs missing starter will barely roll engine over

 

[Jlbc212]

Sounds to me the carburetor is leaking fuel into the cylinder and hydro-locking the cylinder.

^^^ this X3

 

[jkuro]

hydro-locking the cylinder

 

[jimy]

my swisher brush hog had a brake to stop the blade from spinning at shutdown. If you have that, perhaps that is the culprit.

(it also had a lever to engage/disengage the blade, without that there probably isn't a brake)

 

[orangeblood]

check out this site on youtube (steves small engine saloon)

he is pretty good and stays in the small engine space but covers a lot of ground

 

[Jim_No_Garage]

+1 hydro-locking the cylinder

This used to happen on my Toro Lawn Tractor. A fuel line shutoff and we were fine from that point.

Jim

 

[Sh40674]

I should add, the last time it ran (after I cleaned the bowl and sealed the leak from it, I also shot up inside it with carb cleaner) i noticed it didn't run super smooth without the choke 1 click off from the "run" position.. would this point more to hydro lock?

Also, if I pull the plug and turn it a bunch by hand would i be able to see some gas in the cylinder?

 

[LS6 Tommy]

If you can easily spin it by hand with the spark plug out, no gas comes out the plug hole and you have to use the choke to make it run, it isn't hydro locked. If the blades turn without the clutch engaged, look for something mechanical in the driven parts.

Tommy

 

[KenC]

OHV? If so, it is probably in need of a valve adjustment. Real common, even on electric start models to be hard to crank when the valves are too tight.

 

[DanielC99]

X2 on needing a valve adjustment.


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[Busted Knucles]

Timing is too far advanced and firing too soon pushing the piston down before it rolls over top dead center.

 

[Sh40674]

So update and a couple questions...

I adjusted the valves per briggs specs (valves closed roll piston in 1/4" and adjust). The intake was at .011 and the exhaust at .012. Adjusted the intake to .004 and exhaust to .006.

Questions-

1. When I put the plug back in and turned the flywheel by hand it obviously is hard to turn during what I assume is the comp. Stroke... how hard should this be to turn? My worry is when I put the new recoil on i dont want to damage it again. Im used to a snowblower or a push mower, so not sure how hard it should be to turn a 10.5Hp engine. I do have a 500cc 4 wheeler and that pull start is a nightmare but that's also a larger engine. So should be it somewhat hard to turn by hand?

2. As far as the carb.. obviously the engine ran, so the carb somewhat works. Im thinking of taking it off and giving it a quick cleaning as its a walbro and hard to find unless I replace it with an Amazon job... so my question is this... if I put a shutoff valve right before the carburetor, and make sure I shut it when I shut the engine down, should that solve my problem with the carb of it is causing a hydrolock issue? I would check my oil for gas but I ironically changed my oil between when it ran last and when my recoil broke so I cant smell any gas

 

[theoldwizard1]

Timing is too far advanced and firing too soon pushing the piston down before it rolls over top dead center.

Timing definitely off. Hydrolock the engine would not turn over at all.

 

[Sh40674]

Timing definitely off. Hydrolock the engine would not turn over at all.

How does the timing get off?

 

[laser3kw]

So update and a couple questions...
Questions-

2. As far as the carb.. obviously the engine ran, so the carb somewhat works. Im thinking of taking it off and giving it a quick cleaning as its a walbro and hard to find unless I replace it with an Amazon job... so my question is this... if I put a shutoff valve right before the carburetor, and make sure I shut it when I shut the engine down, should that solve my problem with the carb of it is causing a hydrolock issue? I would check my oil for gas but I ironically changed my oil between when it ran last and when my recoil broke so I cant smell any gas

I had this problem with my zero turn. Occasionally, the needle and seat would stick and load up the cylinder. It would manifest itself as a hard start / low battery / slow turn over. I did just as you described and that has worked well for the last two years.

 

[Farmall450]

Sounds to me the carburetor is leaking fuel into the cylinder and hydro-locking the cylinder.

My first thought too given the background. As others have said, pull belt then plug narrow it down

 

[Farmall450]

How does the timing get off?

Partially sheared/bent key on the crank

 

[Sh40674]

Partially sheared/bent key on the crank

Flywheel and shaft are lined up and the key appears to be ok

 

[Wakefield]

Flywheel and shaft are lined up and the key appears to be ok

I don't guess that any Briggs used an offset flywheel key? If so and wrong straight one used could put time off. Think some Tecumseh used such offset keys
could someone have gotten camshaft installed one tooth off?
wrong cylinder head?

 

[Spareparts]

I have run into this problem with B/S engines with the fuel tank mounted above the carb/engine, seems the neddle valve seeps a little fuel into the cylinder and causes this problem, usually after sitting overnight, once it starts it is good the rest of the day or at least for a few hours. I installed a inline fuel shut off valve and instructed the operators to shut it off when finished using it. Never had a problem after that.

 

[Hank11]

I have run into this problem with B/S engines with the fuel tank mounted above the carb/engine, seems the neddle valve seeps a little fuel into the cylinder and causes this problem, usually after sitting overnight, once it starts it is good the rest of the day or at least for a few hours. I installed a inline fuel shut off valve and instructed the operators to shut it off when finished using it. Never had a problem after that.

Its this. ^^^^^^^^^^

Pull the carb and replace the float needle, maybe the float as well. If there is not a fuel cut off, install one in the line from the tank. While you are at it put a filter in there too.

 

[66cj225]

I]Flywheel and shaft are lined up and the key appears to be ok[/I]

You really didn't say whether the unit is new and never ran right or old and beat. Looking up the Briggs IC 10.5 shows an automatic compression release on the new engine technical spec. Not being privy to your model #, your results may vary. I'd investigate this first.

When an IC engine is stopped abruptly, the flywheel tries to keep going, advancing the spark. The flywheel key is either aluminum or steel. Steel keys can damage the crankshaft opening, sometimes they can be wedged back into place to work. Aluminum, just replace it if it has so much as a line on it.

I agree with the pull the belt, fuel shutoff, need to check the auto compression release, pull the flywheel and replace the key, and check the coil mounting. Rattle gun that flywheel nut back on. (Bat or air)
There's no way and healthy engine should bite you like that.
Good luck.

 

[firebirdparts]

I totally disagree with hydrolocking. Really disagree. It sounds like the timing is too advanced, but even if that's true, you do need to adjust the valves first. Always.

That said, it takes some a$$ to pull start a 10 hp motor no matter what. All the more reason the timing needs to be backed off..

 

[KenC]

So update and a couple questions...

I adjusted the valves per briggs specs (valves closed roll piston in 1/4" and adjust). The intake was at .011 and the exhaust at .012. Adjusted the intake to .004 and exhaust to .006.

Questions-

1. When I put the plug back in and turned the flywheel by hand it obviously is hard to turn during what I assume is the comp. Stroke... how hard should this be to turn? My worry is when I put the new recoil on i dont want to damage it again. Im used to a snowblower or a push mower, so not sure how hard it should be to turn a 10.5Hp engine. I do have a 500cc 4 wheeler and that pull start is a nightmare but that's also a larger engine. So should be it somewhat hard to turn by hand?

2. As far as the carb.. obviously the engine ran, so the carb somewhat works. Im thinking of taking it off and giving it a quick cleaning as its a walbro and hard to find unless I replace it with an Amazon job... so my question is this... if I put a shutoff valve right before the carburetor, and make sure I shut it when I shut the engine down, should that solve my problem with the carb of it is causing a hydrolock issue? I would check my oil for gas but I ironically changed my oil between when it ran last and when my recoil broke so I cant smell any gas

If the engine is in good shape, there will be a lot of compression. With the valves as loose as you found them a lot of the compression release function is lost

Have you tried to start it since setting the valves?

If not, remove the spark plug and pull it over just to assure that not fuel is in the cylinder. Then put the plug in and try it. That will remove any doubt as to the hydro-lock theory if it is still bad. If it starts the valve adj fixed it. If not, check back. I think the next step would involve a cam change as the compression release may not be working.

 

[greg13]

Valve clearance most important, that will throw the de compressor off. Flywheel key will throw the timing off. One or both of them.

 

[ericm]

If it's hard to pull with the spark plug disconnected, it's the decompressor. If it pulls ok but kicks back when starting, the timing is off.

 

[101SCOUT]

So tell us your model type and code, that tells us the type of briggs engine you have. If your valve setting are matching your engine it is a ohv engine and you are in the specs needed.
If you have an ohv engine pull your valve cover and pull your spark plug and watch the exhaust valve to see if it is bumped off the seat on compression stroke, if not you need a camshaft its a known problem on briggs singles.
As far as the carb leaking again if it is an ohv engine you can get a seat kit to stop the needle from leaking, you have to pull the brass seat out of the carb and install a new seat and needle, shut off vale was our way of fixing them before seats were made available.
Trust me on this I have done 75 to 100 of these camshaft problem engines, not saying anyone elses help is wrong but these are first steps to fix problem. the reason you hit the wall is either compression release or combination of hydro lock from excess gas in combustion chamber and you cant compress a liquid.
CHECK FOR EXHAUST VALVE MOVEMENT FIRST, IT WILL BE YOUR PATH OF LEAST RESISTANCE.

 

[Sh40674]

So tell us your model type and code, that tells us the type of briggs engine you have. If your valve setting are matching your engine it is a ohv engine and you are in the specs needed.
If you have an ohv engine pull your valve cover and pull your spark plug and watch the exhaust valve to see if it is bumped off the seat on compression stroke, if not you need a camshaft its a known problem on briggs singles.
As far as the carb leaking again if it is an ohv engine you can get a seat kit to stop the needle from leaking, you have to pull the brass seat out of the carb and install a new seat and needle, shut off vale was our way of fixing them before seats were made available.
Trust me on this I have done 75 to 100 of these camshaft problem engines, not saying anyone elses help is wrong but these are first steps to fix problem. the reason you hit the wall is either compression release or combination of hydro lock from excess gas in combustion chamber and you cant compress a liquid.
CHECK FOR EXHAUST VALVE MOVEMENT FIRST, IT WILL BE YOUR PATH OF LEAST RESISTANCE.

So explain in detail where I'm looking for movement? Still waiting for my recoil to show up. Have a needle and seat that arrived in the mail already

 

[KenC]

So explain in detail where I'm looking for movement? Still waiting for my recoil to show up. Have a needle and seat that arrived in the mail already

With the valve cover off observe the exhaust valve as it approaches TDC compression. It should be fully seated as the piston rises, but shortly before TDC, it should open slightly and then close again

That is the compression release provided by the cam.

 

[Sh40674]

With the valve cover off observe the exhaust valve as it approaches TDC compression. It should be fully seated as the piston rises, but shortly before TDC, it should open slightly and then close again

That is the compression release provided by the cam.

Thanks I'll check this weekend. Didn't look for that after I adjusted the valves