Kohler Magnum 20 Starting problem with video

buzbo · Dec 4, 2017

Hello all,

I have a Kohler Magnum 20 (or 18) powering a mid-90s Vermeer 620 woodchipper. All was running well 1-2 years ago until it sat over a Northeast winter.
The engine would not move when I tried to start it this summer. I added oil into each cylinder, let it sit, and eventually got the flywheel moving. After replacing the battery, it now cranks well but will not fire. Here's what I've done:

-Swapped out the gas and tank with fresh fuel and a clean pony tank with a new filter.
-Cleaned (fairly well) carb: removed rust and stains. Gasket is not in great condition but it seems to still provide a good seal. I have not adjusted any needles or screws.
-Used starting fluid sparingly (4-5 times); would fire but not start.
-Tested sparkplugs (two different types of plugs): both sparked, small, but still a spark.

As the video shows, there is oil spitting out the breather tube (dirty, too). I assume because there is too much oil in the cylinder from freeing it up. I removed the breather tube cap and gasket while starting in the video. I am going to change the oil next. Not sure what else to do.

I have successfully tinkered with some small engines in the past but I am far from an expert. Looking forward to utilizing this great resource. Thanks for all your advice!

I'm too new to post a link so bear with the copy, paste, and edit.

video: youtu [.] be/vkaayfp5IuE

-Buz

dfbroxy · Dec 5, 2017

Hi buzbo, let me start off by saying welcome to the forum.
First thing first, the experts on this site will need your make and model number. Its stamped on one of your valve covers. I am not one of the experts, but a tinkerer like yourself. I retired 6 months ago and needed to rebuild my 25hp briggs so I joined this forum and started watching vidios on google. Now after the rebuild she runs like new. Make use of both of those and you will never have a small engine in the shop.
Thats my advice now to your engine. Use gas instead of starter fluid to avoid the chance of engine damage. I would start with checking the pushrods and valve adjustment. There are some very good vidios on google if you dont know how. As I am unfamilar with your engine I dont know if it has a fuel siloniod on the carb, but if it does check the operation of it.(google) After doing this hook jumper cables to it and try to start again, several times. If it doesnt start pull plugs and clean if they are wet with oil. With plugs out turn engine over to clear cylinders. Reinstall plugs and try to start again. If this doesnt work, post again and give us a update.

bertsmobile1 · Dec 5, 2017

buzbo said:
Hello all,

I have a Kohler Magnum 20 (or 18) powering a mid-90s Vermeer 620 woodchipper. All was running well 1-2 years ago until it sat over a Northeast winter.
The engine would not move when I tried to start it this summer. I added oil into each cylinder, let it sit, and eventually got the flywheel moving. After replacing the battery, it now cranks well but will not fire. Here's what I've done:

-Swapped out the gas and tank with fresh fuel and a clean pony tank with a new filter.
-Cleaned (fairly well) carb: removed rust and stains. Gasket is not in great condition but it seems to still provide a good seal. I have not adjusted any needles or screws.
-Used starting fluid sparingly (4-5 times); would fire but not start.
-Tested sparkplugs (two different types of plugs): both sparked, small, but still a spark.

As the video shows, there is oil spitting out the breather tube (dirty, too). I assume because there is too much oil in the cylinder from freeing it up. I removed the breather tube cap and gasket while starting in the video. I am going to change the oil next. Not sure what else to do.

I have successfully tinkered with some small engines in the past but I am far from an expert. Looking forward to utilizing this great resource. Thanks for all your advice!

I'm too new to post a link so bear with the copy, paste, and edit.

video: youtu [.] be/vkaayfp5IuE

-Buz

firstly your link is all messed up so you might like to try to upload the URL again.

Next use a teaspoon of fuel down the carb throat.
If it runs through the fuel, should be 10 to 15 seconds then you can assume that the engine is OK and you have a fuel supply problem to the carb.
If your engine has a fuel solenoid, check that it is working by replacing it with a bolt.
Runs ok = dodgy solenoid or wiring to it.

Give it a whirl & get back.

buzbo · Dec 5, 2017

Thank you for your advice.

As I'm new- I cannot post a direct link. If you want to watch the video you have to remove the brackets and tighten it up.

I will try the fuel in carb next. Even if the oil is bad (dirty/too much), it should still fire up which narrows it down to a fuel or carb problem--correct?

buzbo · Dec 19, 2017

Thanks for the replies.

Adding a shot of gas into the carb results in a fire with the choke out. But it only fires and does not run beyond a second or two.

Kohler model #: M20S
Spec #: 49581
Serial#: 2422402276

The oil that blows out of the breather is grey. That's getting changed today- though I don't believe that's the source of my starting problem.

This model does not have a solenoid carb. I haven't seen a lot of this model engine on YouTube. There are a ton of newer courage engines in small tractors and lawn mowers. I have read that these engines often need a valve adjustment after sitting for extended periods.

As a new member, I can't paste a direct link, hence the the [ ]. If you paste the whole thing into a google search bar it is the first result "kohler Start". Thanks again!

bertsmobile1 · Dec 19, 2017

Sorry I did not know about the no-link for new members .
They made some changes a while back to deteer spammers, that must have been one of them.

If you are getting good fuel supply to the carb then.
Your carb is dirty and will need to come off, get fully stripped down and cleaned properly.
Should find step by step instructions here http://outdoorpowerinfo.com/repairs/
Grey oil is a sign that there is water in there and most likely some fuel as well so change it right now then again after the first hour or so

buzbo · Jan 27, 2018

Update:

The original carb was beyond cleaning--with rust and broken gaskets. I found a cheap replacement which I installed and got the engine running nicely. I haven't done any adjustments on the new carb.

I changed the dirty and watery oil. I ordered a new filter which I'm still waiting to arrive. After changing the oil--twice--the dipstick is still showing grey oil after running the engine. Hopefully this will change when I put in the new filter?

---Two new issues are getting fuel into the carb and excessive smoking while running.

The engine seems to run healthily. A couple of high revs produced some rusty-looking exhaust, but it seems to run and idle fairly well....The gas problem allowed me to run it for about five minutes until the tank ran low. Upon starting up the first few times, then after shutting down, there was quite a bit of white smoke exiting out of and around the exhaust. I'm thinking once I get the filter and some continuously clean oil, that may subside.

Gas problem-- the gas only flows from a gravity-fed auxiliary tank I set up. When trying to feed from the factory tank, located below the engine, it will not draw fuel. Is there a mechanical fuel pump that could be stuck?

Thanks for the responses so far. They definitely got me on the right track!

--Buz

bertsmobile1 · Jan 28, 2018

There could be either a mechanical or impulse fuel pump, kohler used both of them from time to time.
There is a kit available to convert from mechanical to impulse which will cause far fewer problems.
Follow the fuel lines from the tank.
If it goes into a "box" with 2 other tubes plugged into it it is an impulse pump.
If there are just 2 fuel lines then it is a mechanical pump.

Water will continue to come out for a long time.
I generally advise buying some cheap ( K-mart , HF, Walmart etc ) oil and do multiple oil changes with about 1/2 our to 1 hour between them.
When the last of the cheap oil goes in replace the filter and then after an hours mowing replace the oil with good quality mower oil.

Oil in the muffler & air box will ake some time to burn off but will do it eventually.
Run the moower for a good 5 to 10 minutes, shut it down then wait another minute.
Remove the dip stick.
If smoke comes out of the dip stick hole then the head gasket or rings are toast.

buzbo · Jan 30, 2018

It's a mechanical fuel pump. Do these just wear out over time/extended storage? The engine was running well about 2 years ago before it sat..

The kohler online parts catalog was useful in IDing it, and it's 70% cheaper on amazon...I'm still trying to locate the kit that converts to impulse --which is the same as a vacuum pump?

My gravity fed aux fuel tank has been helpful in getting the engine running but it burns through fuel. Is this because the fuel runs straight through the pump, unregulated?

bertsmobile1 · Jan 30, 2018

buzbo said:
It's a mechanical fuel pump. Do these just wear out over time/extended storage? The engine was running well about 2 years ago before it sat..

The kohler online parts catalog was useful in IDing it, and it's 70% cheaper on amazon...I'm still trying to locate the kit that converts to impulse --which is the same as a vacuum pump?

My gravity fed aux fuel tank has been helpful in getting the engine running but it burns through fuel. Is this because the fuel runs straight through the pump, unregulated?

Yes the vacuum pump & the impulse pump are one & the same thing,
The parts you need are a rocker cover with a hole in it , a pump & a cover plate to go over where the original pump was.
There was a kit that had a spigot in the cover plate but it is not a genuine Kohler part.

The amount of fuel you use has noting to do with what type of pump you are using, the carburettor controls the fuel.
If the float valve in the carb is not working properly then the fuel will vanish but it is most likely just an illusion if the gravity tank is small.

Kohler Magnum 20 Starting problem with video

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