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I had a Kohler Courage 25HP twin on a Husqvarna 54 inch riding mower give it up on my a couple years ago. That engine was nothing but trouble and I wasn't too upset when it finally gave it up for good. The Command is great but the Courage is terrible. I ended up parking the unit as the rest of the mower was in great shape. I didn't want to pay the price of buying a new engine for the unit as they cost as much as the entire machine. I ended up using a couple used beaters for the time being but ended up with a nice commercial zero turn. I was about to scrap the mower or selling it cheap for parts when a junked mower very similar to mine came along with a working engine.

The unit was parked a couple years ago due to a broken axle in the transaxle. The shaft was cracked in two. The engine was running when it was parked but no preparation was taken to store it and the old gas was left in it. This engine is a Briggs and Stratton Vanguard 26HP V-twin so I swapped it in for my junk Kohler Courage. The numbers on the engine valve cover are MODEL: 445877 TYPE: 0760 B1 CODE: 080228YG. It bolted up and all the connections fit exactly as they did on the old Kohler without modification. I dropped the bowl and cleared out the old gas. I sprayed carb cleaner through the jets and they appeared clean.

Anyway, the engine started up on the first try and ran great at idle. Once loaded, the governor opens up the throttle further and then the engine starts flooding. The governor keeps the throttle plate open wide and the engine just stumbles and barely stays running while spewing thick black smoke. The engine acts EXACTLY like one would act if you pulled the choke closed while the engine was running and warmed up yet the choke is open. If you pull the choke while it is doing this, the engine will completely flood and die.

The engine will come back to life if I unload it and manually pull the governor level back to where the throttle is barely open. I haven't even tried putting the deck on but running the transmission at full speed will force the governor to open the throttle far enough to where the engine starts flooding and sputtering with lots of black smoke. The engine recovers as soon as I put the transmission in neutral and back the throttle off to low.

I don't know if I am missing something but this seems to be related to throttle position and not engine load. A load causes the governor to open the throttle more and then the symptoms start. Backing the throttle off resolves the symptoms. It looks like there is more to this carb and was wondering if there are some type of secondary jets that may be open too far. This only starts when the throttle is open beyond a certain position and will not recover on its own.

I figure a tear down of the carb is in order but wanted to ask here first in case I am missing something simple. Remember this thing sat for a while. I have changed the oil already and plan to change the transaxle fluid in my unit once I get the engine lined out.

Let me know what suggestions you may have.

Thanks.

I have one possibility to explore. I had removed the jets to clean them. I would say there is a 50% chance I put them in the wrong way. I thought they were the same but the parts diagrams all show a left and right jet so apparently this is important. So they will be swapped tomorrow when I get into this and see what that does.

Could having the jets reversed cause this type of flooding behavior at full throttle? I figure it might not be ideal but would be surprised if it makes that big of a difference.

Not familiar with your engine but what you are describing is exactly what happens when you forget to put the main jet back in.
Runs fine on th idle circuit but as soon as it tries to run on the main jet it get 50 times as much fuel as it should.

Not enough difference in the jet sizes even if on wrong side to cause what you are saying. Most likely you are missing a jet.

Thanks. I will pull the bowl off when I get time later today. I wondered if I forgot to put a jet back in and even dropped the bowl to check. This was a possibility for me as well since the jet is a restriction to meter the fuel and it would completely dump it if it were missing. Both were in the carb but I will check again.

Are there any numbers on the jets to designate which is which? It seems that these are so small and I don't know where the stamping, etc. would go.

Thanks.

I removed the bowl and both jets were there. I then removed and re-cleaned the entire carb again and took more things apart. I did re-clean and re-seat them with a thin film of black RTV around the outside. I then pressed them back in as far as they would go. I tried again and the same thing happened. I have been all through this carb and it isn't complicated so feel my issue is something else. The flywheel to coil gap looked a little large so I re-gapped that with card stock (cannot find my feeler gauge). It was a little far out and card stock is often provided with new coils as the method of gapping.

I MIGHT have been a little better after this but still did it. I am going to change the plugs next and am going to go buy them in a little bit. I have seen plugs do some odd things in the past. The engine starts and idles great but it is like it cannot burn the fuel being provided at higher loads. Plugs are easy so figure that is next in line.

Then I also saw someone on another forum/thread with a similar problem suggesting that the valve lash may be out. If the plugs do not fix it I will go get a feeler gauge and make sure my valve lash is to spec. My lash settings for intake and exhaust are .004-.006. See https://www.vanguardengines.com/con.../files/Engine Specifications Chart_ms3992.pdf and look at OHV twin cylinder series 445000. The engine seems to have decent compression and the intake valves feel like they are fully closing. Intake valves not fully closing from incorrect lash have been suggested as a possible culprit in other similar situations.

Is this engine a Vanguard or an Intek/ELS vertical twin?

OK, a couple things.... This engine is an INTEK and not a Vanguard. I was told it was a Vanguard and got it for $50 as part of an entire parts unit. It all happened very fast and I didn't pay a lot of attention. I made sure the engine was free and had compression, then loaded it up into my truck. Either way, I finally got my issues resolves and re-assembled the unit and put the housing back onto the engine. It says INTEK big as life so this is not a Vanguard. I was hoping for a Vanguard but for $50 for a 26HP I am not too upset. I kinda had to really jump on the opportunity to get this and had to scramble to get out and pick it up.

How reliable is the INTEK overall compared to the Vanguard? I know some of the single cylinder cheapos are not too hot and have had experiences with them eating valve seats/valves myself. Are the larger twins a little better?

On to the flooding problem that started this thread.... It was my partly my fault from the start. It appears the jets had been installed incorrectly when I got it and the parts diagram was confusing. Basically I had the jets in the wrong hole (it was confusing) and the carb was behaving as though no jets were installed. I took the carb to my local mower shop when getting new plugs for the unit. I was showing them how clean I had gotten the unit and they pointed out immediately that I had the jets in the wrong location. They said this is something that anyone could do based on the parts diagram and that you have to learn from experience on these things. This unit had been molested a bit with missing bolts and a few other parts (now replaced) so guess this was part of that. I still can't complain for $50.

So, I put the carb back on with new plugs installed and it started up and ran normally. It would start without the choke before while this is required now that it isn't getting so much gas. It has fresh oil and a new filter as the oil looked pretty bad as well.

The problem is solved!

cmw said:

OK, a couple things.... This engine is an INTEK and not a Vanguard. I was told it was a Vanguard and got it for $50 as part of an entire parts unit. It all happened very fast and I didn't pay a lot of attention. I made sure the engine was free and had compression, then loaded it up into my truck. Either way, I finally got my issues resolves and re-assembled the unit and put the housing back onto the engine. It says INTEK big as life so this is not a Vanguard. I was hoping for a Vanguard but for $50 for a 26HP I am not too upset. I kinda had to really jump on the opportunity to get this and had to scramble to get out and pick it up.

How reliable is the INTEK overall compared to the Vanguard? I know some of the single cylinder cheapos are not too hot and have had experiences with them eating valve seats/valves myself. Are the larger twins a little better?

On to the flooding problem that started this thread.... It was my partly my fault from the start. It appears the jets had been installed incorrectly when I got it and the parts diagram was confusing. Basically I had the jets in the wrong hole (it was confusing) and the carb was behaving as though no jets were installed. I took the carb to my local mower shop when getting new plugs for the unit. I was showing them how clean I had gotten the unit and they pointed out immediately that I had the jets in the wrong location. They said this is something that anyone could do based on the parts diagram and that you have to learn from experience on these things. This unit had been molested a bit with missing bolts and a few other parts (now replaced) so guess this was part of that. I still can't complain for $50.

So, I put the carb back on with new plugs installed and it started up and ran normally. It would start without the choke before while this is required now that it isn't getting so much gas. It has fresh oil and a new filter as the oil looked pretty bad as well.

The problem is solved!

Click to expand...

THANKS for your update on your carb with your PROBLEM SOLVED , I'm sure this will be very helpful to some other members !! ..:thumbsup:

cmw said:

OK, a couple things.... This engine is an INTEK and not a Vanguard. I was told it was a Vanguard and got it for $50 as part of an entire parts unit. It all happened very fast and I didn't pay a lot of attention. I made sure the engine was free and had compression, then loaded it up into my truck. Either way, I finally got my issues resolves and re-assembled the unit and put the housing back onto the engine. It says INTEK big as life so this is not a Vanguard. I was hoping for a Vanguard but for $50 for a 26HP I am not too upset. I kinda had to really jump on the opportunity to get this and had to scramble to get out and pick it up.

How reliable is the INTEK overall compared to the Vanguard? I know some of the single cylinder cheapos are not too hot and have had experiences with them eating valve seats/valves myself. Are the larger twins a little better?

On to the flooding problem that started this thread.... It was my partly my fault from the start. It appears the jets had been installed incorrectly when I got it and the parts diagram was confusing. Basically I had the jets in the wrong hole (it was confusing) and the carb was behaving as though no jets were installed. I took the carb to my local mower shop when getting new plugs for the unit. I was showing them how clean I had gotten the unit and they pointed out immediately that I had the jets in the wrong location. They said this is something that anyone could do based on the parts diagram and that you have to learn from experience on these things. This unit had been molested a bit with missing bolts and a few other parts (now replaced) so guess this was part of that. I still can't complain for $50.

So, I put the carb back on with new plugs installed and it started up and ran normally. It would start without the choke before while this is required now that it isn't getting so much gas. It has fresh oil and a new filter as the oil looked pretty bad as well.

The problem is solved!

Click to expand...

Well that explains why it was $50 and not $ 500 .
Lucky you silly him.
Inteks are cheapened down versions of Vanguards.
Not sure about the twins but the singles have thinner castings and that makes them very sensitative to overheating and they regularly blow head gaskets between the cylinder & pushrod tube.
So keep the engine clean UNDER the blower housing , check the valve lash regularly and watch the oil level and you should get good use out of it depending upon how much abuse has been inflicted on it beforehand.

Yeah, I was pretty happy to get it for $50 and am glad how things are going so far. I had a single 16.5HP or so that dropped a valve seat which caused the valve to break off in the cylinder. This was then forced through the head and destroyed it. The piston was dented and likely weakened. I found a used head and installed it. I set the valve lash to spec and went on with business. It ran well for a while and then the same thing happened again with the other valve. This time it busted a hole in the piston and I junked the unit and replaced it with a 16HP Kohler Command which has been excellent.

The fins on this Intek were pretty clean. I had the housing off to do the work and it looked like there wasn't any debris blocking the fins so hopefully it was kept cool. The oil was dirty and pure black but the insides of the valve covers were clean when I checked the lash (it was right on). The valve covers are always where the sludge forms because of their relatively cool temps so was happy to see that they were clean.

I got the fluid in the transaxle changed as well and have started using it to mow. There are a few other little things I need to do but overall the project of bringing my LGT 2554 back to life is completed.

This seemed to mow well but I only have one issue. The engine seems to run-on and diesel after I turn it off, sometimes with loud backfires. This also happens if I happen to raise up off my seat while mowing. I suspect the anti-backfire solenoid is giving me issues as these seem to do more harm than good from my experiences. Usually shutting down with the deck engaged will stop this but this one will actually continue to mow with the key off. Pulling the choke kills it but I hate flooding the engine with all that gas.

The engine definitely ran smoother with more use. Maybe there are deposits from the rich running that are now burning off. I did install new plugs at the same time I solved the flooding issue so assume it isn't the plugs.

Slip a spark tester on the plug and see if it is still sparking after you turn it off.
If so then the kill circuit is broken / disconnected somewhere

If no spark then try a plug 1 grade colder.

I think the issue of the backfiring and run on was related to the engine sitting and maybe deposits that formed from the rich running condition. Either way this seems to have worked itself out with simply running the mower a few hours mowing and keeping the engine under load.

Anyway, I think this thing is going to work out OK once I get a few small bugs worked out of it. Thanks.

The new lean burn engines run way too hot for air cooled engines so yes carbon buildup will be an ignition source after the ignition is turned off.
The fuel shut off solenoid should also kill the engine by starving it however if this is the case the carbon should not build up unless there is a significant oil leak.
Not uncommon to find kill wires not connected on used mowers bought from redneck anti government conspiracy no nanny state types.

The fuel shutoff solenoid appears to be molested so I think that is part of it for sure. The last time I looked these were like a $300 part so may just live with it. Either way, the run-on issue appears to have stopped after some use. There is just a nice loud backfire from time to time at shutoff. Running the engine for a while appears to have burned off some carbon.

The unit doesn't appear to be burning oil. I agree with you that modern small engines run way too lean, likely contributing to higher temps and a backfire at shut-off. For this reason I run synthetic oils in everything I own. This one has a Rotella T6 5W40 which I have had good luck with in other engines. Engines that do use a slight bit of oil usually clear up when I use this oil. It is a diesel rated synthetic so has more detergents and anti-wear additives. Most of the stuff I get is gotten with problems so I get it cheap. Often the engines have been neglected. This Rotella seems to free up sticky rings, etc.

The jets are fixed orifices and there is no adjustment besides replacing the jets. Unfortunately the available replacement options are leaner yet for high altitude operation.

Anyway, thanks again. This thing is coming together bit by bit.

If your problem is a build up of carbon fitting a tap in the fuel line and shutting off the fuel to starve the engine will go a long way to cleaning it up.
Just do not forget to turn the engine off after it stops running or you will flatten the battery.