# Kohler M18QS engine problems..



## eltro (Aug 16, 2006)

*Kohler M18QS engine problems..Fixed*

I have an old riding law mower that i purchased and i'm trying to get it running right. It has a Kohler M18QS emgine. The engine has an ok idle at low or high throttle position. One problem that i have, is that I have to put in some gas or carb cleaner in the carburater before it can start. second, after it starts if I try to accelarate the engine will hesitate and will only advance a bit. If I keep accelarating more the engine dies. I can put the peddle to the metal and it will spin the tires and then finally die unless i let go of the peddle. could the fuel/air mixture be incorrect? timing? Where can i get a manual? TAnything will help. thanks!


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## bugman (Aug 12, 2004)

Carb, sounds like it needs a good carb rebuild (tear down, soak in carb cleaner, blow out with air and a rebuild kit installed)


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## TechLarry (Aug 2, 2006)

Yep. ya just don't get away with leaving gas in an old engine for a few years 

Even Stabil can't last forever.

-Larry


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## eltro (Aug 16, 2006)

I just finished tearing down the carb and already cleaned it with carb cleaner. I seem to have stumbled into an issues, or atleast I think it is one. There is a needle that goes right in the center or the carb, right above the diaphram (it's more a floater in this one), that seems to be bent so it's not right in the center. I shed some light through the hole where the needle is at and noticed there is something in there making the needle bend. I already triend poking it with a needle but it doesn't seem to budge. I really can't see what it is because the hole is so small. I can't tell if it's dirt or part of the carb. Is that normal or is the needle suppose to be straight?


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## TechLarry (Aug 2, 2006)

I only know the 18 Command Series carb (just rebuilt mine).

Here is what mine looks like. Is yours the same?

These are before the rebuild

-Larry


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## eltro (Aug 16, 2006)

My carb seems to be different. I took some pictures and also tried to take one of the needle i'm talking about. I tried looking through the hole again and it seems that the there is nothing stuck inside but the needle has a "v" groove, kinda looks like this, "-----^-----". maybe i'm wrong, i don't know i haven't found a manual yet. anyways here are some pics. not the best and i had to resize them to less than 50kb but if you look closely you can see the needle is not centered.


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## TechLarry (Aug 2, 2006)

Sorry. What needle 

What kind of carb is it?

I can find practically nothing about an 18qs in google, and Kohler's web site doesn't have a clue either.

-Larry



eltro said:


> My carb seems to be different. I took some pictures and also tried to take one of the needle i'm talking about. I tried looking through the hole again and it seems that the there is nothing stuck inside but the needle has a "v" groove, kinda looks like this, "-----^-----". maybe i'm wrong, i don't know i haven't found a manual yet. anyways here are some pics. not the best and i had to resize them to less than 50kb but if you look closely you can see the needle is not centered.


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## TechLarry (Aug 2, 2006)

Good heavens! That's an old Magnum engine. Look at the prices for these things!

M18QS-24532 18 HP Magnum Horizontal 1"x2 3/4" Shaft electric start fits M & W Gear, Grazer, DROP SHIP ONLY $2,660.00 
M18QS-24608 18 HP Magnum Horizontal 1"x2 3/4" shaft exact for Grasshopper, Woods $2,435.00 
M18QS-24646 18 HP Magnum Horizontal 1-1/8"x2 51/64" electric start fits some Cub Cadet $2,280.00 
M18QS-24696 18 HP Magnum Horizontal 1-1/8"x2 37/64" shaft electric start fits Melroe Bobcat, DROP SHIP ONLY $2,290.00


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## eltro (Aug 16, 2006)

Yes I tried finding something on Google also but came out empty handed. The only things I could find was ads on the engines, yes I was surprised also on how expensive they are! I already sent an email using the Kohler website about acquiring a manua. Hopefully they respond soon.

If you look closely at the first picture, in the very center there is a needle. Sorry my camera is too good. Here, I circled the part where the needle is at, I don't know what it's called either but here is it. You might have to look closely.


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## TechLarry (Aug 2, 2006)

I can see the hole, but not what's in it.

Does your camera have a "Macro" mode? That might help.

-Larry



eltro said:


> Yes I tried finding something on Google also but came out empty handed. The only things I could find was ads on the engines, yes I was surprised also on how expensive they are! I already sent an email using the Kohler website about acquiring a manua. Hopefully they respond soon.
> 
> If you look closely at the first picture, in the very center there is a needle. Sorry my camera is too good. Here, I circled the part where the needle is at, I don't know what it's called either but here is it. You might have to look closely.


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## eltro (Aug 16, 2006)

I just put the carb back on today since I just bought some spark plugs for the engine. It seems that it can start now without adding any gas to the carb but it still doesn't run when I try to accelarate using the pedal or engage the PTO. I can rev the engine manually and it will run fine. I have found out that by pressing the pedal forward or reverse or engaging the PTO, it activates the clutch and that's when the engine starts failing. This leads me to believe the clutch needs some servicing but unfortunatly i've never done one. I will probably end up taking off the clutch but before that, what should I look for? What do I need to do to it? Lube it? Thanks. BTW. this is a Toro riding lawnmower.


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## kyoshorunner (Mar 3, 2003)

What kind of Toro tractor is it? I've got an older Toro HMR 1600 that just had one of the hydrostatic drives fail. The motor is a 16 HP Kohler that runs O.K. but it does smoke a little when first started.


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## eltro (Aug 16, 2006)

*Issue fixed*

Well I thought just like everyone else that it was the carburator or the electric PTO. Well It turns out that it actually a faulty relay that connects to the ignition switch and the electric PTO. I was playing around with it trying to adjust the fuel/air misture and decided to disconnect this relay and surprisingly it starting advancing forward, reverse, and even engaging the PTO. I'll have to replace the relay so I can turn it on with a key because right now I'm starting it by connecting the starter solenoid ends with a screwdriver. Now I just have to go pick up the attachments and test it out. It only has 600+ hours so it should last a while. I don't know what kind of mower it is but it's a pretty old one, it's a model 30735 I belive. Thanks for all your help! :thumbsup: 

Oh btw...is the choke suppose to be ON or OFF? When it's on ON it runs but when I switch it to OFF the motor dies. just wondering because it seems off to me. Here's a picture of a Toro that looks exactly like mine exept for minor differences like the muffler and mine's not diesel http://i17.ebayimg.com/06/i/08/25/78/3f_1.JPG . thanks again.


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