Hard hot starting on a 454 ss | TruckMount Forums #1 Carpet Cleaning Forums

Hard hot starting on a 454 ss

HiCrestRick

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My 454ss lately has been starting erratically when hot. It popped out of the carburetor a couple times, then it starts going, hesitates a little, then runs strong again. I'm leaning towards a failing fuel pump, no pun intended, any thoughts would be appreciated...btw it's a 35hp Briggs and Stratton, air cooled, not the liquid cooled...
 

JDARNOLD

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It could be a gas issue. If it only has the starting problem when it is hot, and restarting check the fuel line around the motor it could be heat from the engine causing vapor locking. But if you have 1k hours or more and takes more than a few seconds to get started. Then I suggest getting the valve backlash checked and adjusted if needed. I know most don't do it but Briggs says this should be done yearly.
 
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Todd the Cleaner

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I have the 40HP kohler air cooled and it’s been like that from day one. If the engine is cold it fires right up but if I shut off the machine and try to start it again within 30 minutes it floods every time making it hard to start. When it does start it runs rough for the first 20 seconds then it runs just fine until I shut it off again. This is a known problem among kohler 40HP engines and like I said it’s been this way since the engine was brand new.

I’ve been thinking I’m going to try putting a shut off valve on the fuel line and see if I can fix the problem that way. I’ll shut off the fuel just before shutting off the machine and then open up the fuel line after re-starting. I’ll get this done this week and report back.

@HiCrestRick it sounds like you may be having the same issue.
 
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Anderson

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I have the 40HP kohler air cooled and it’s been like that from day one. If the engine is cold it fires right up but if I shut off the machine and try to start it again within 30 minutes it floods every time making it hard to start. When it does start it runs rough for the first 20 seconds then it runs just fine until I shut it off again. This is a known problem among kohler 40HP engines and like I said it’s been this way since the engine was brand new.

I’ve been thinking I’m going to try putting a shut off valve on the fuel line and see if I can fix the problem that way. I’ll shut off the fuel just before shutting off the machine and then open up the fuel line after re-starting. I’ll get this done this week and report back.

@HiCrestRick it sounds like you may be having the same issue.
DOES kholer still make the 40hp???????

i can only find a kholer 37hp
 

Todd the Cleaner

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DOES kholer still make the 40hp???????

i can only find a kholer 37hp
I feel cheated! I guess they changed the rating of the 40 to a 37

Here’s the engine I have.

068E4020-472D-4849-AEA5-8D4802293734.png
1E3D7314-4BD5-47DC-907E-F4D2873E6F8A.jpeg
 

HiCrestRick

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I have the 40HP kohler air cooled and it’s been like that from day one. If the engine is cold it fires right up but if I shut off the machine and try to start it again within 30 minutes it floods every time making it hard to start. When it does start it runs rough for the first 20 seconds then it runs just fine until I shut it off again. This is a known problem among kohler 40HP engines and like I said it’s been this way since the engine was brand new.

I’ve been thinking I’m going to try putting a shut off valve on the fuel line and see if I can fix the problem that way. I’ll shut off the fuel just before shutting off the machine and then open up the fuel line after re-starting. I’ll get this done this week and report back.

@HiCrestRick it sounds like you may be having the same issue.
That sounds like exactly the same problem...I am going to try setting the valves, the engine has about 1300 hours, it runs strong, but any problem I get that happens twice I try to be proactive about, so I'm cool with you doing the experimental fix, it sounds like something I would try, if it works I'll implement the same thing, and tell people it was my idea;) jk, thanks for the feedback
 

HiCrestRick

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It could be a gas issue. If it only has the starting problem when it is hot, and restarting check the fuel line around the motor it could be heat from the engine causing vapor locking. But if you have 1k hours or more and takes more than a few seconds to get started. Then I suggest getting the valve backlash checked and adjusted if needed. I know most don't do it but Briggs says this should be done yearly.
I'm going to set the valves this week, it has 1300 hrs and was probably never done, can't hurt anything, and while i'm at it I'll inspect the fuel line as well. Thanks for the feedback
 

Todd the Cleaner

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Tried that, instantly floods it, then I have to wait at least 15 minutes and it starts acceptably
I can usually get mine started within a couple minutes, I stand there holding the starter key for about 10-15 seconds then give it a rest for another 10 seconds and try starting again. I do have the throttle up at about 2/3 open while dong this. Usually after 4 or 5 times of cranking it for 15 seconds it will start and run rough until it burns off the excessive fuel then it runs great. I absolutely hate doing that because I know I’m killing the starter.
 
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JDARNOLD

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Another thing it could be is oil pressure, if it has a oil pressure switch and you are using a multi grade oil. Such as 5w30 mobil 1 like Briggs and Stratton recommend it could be the oil is thinning out when it gets hot. Talk to your local small engine mechanic, ask what oil they use in Briggs motors. I'll bet it is straight 0w30. I put 0W30 Mobil 1in my customers Briggs motors and have never had problems. Just serviced on this past week with 4200 hrs and still running. Just something to look at.
 
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JD5150

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I'm using the 35 Briggs on my machine. Put a switch on the fuel pump so you can shut it off. That makes it easier to hot start. I start mine at half throttle fuel pump off. Might be getting time to adjust the valves. Might need a new air filter.
 
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cptuphcln

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This is Scott With Legend Brands, Has the fuel filter with the return been changed recently?
sounds like too much fuel is getting to the carb, is the choke sticking? Fell free to contact me at 866-445-3030 ext 4007
 

HiCrestRick

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I can usually get mine started within a couple minutes, I stand there holding the starter key for about 10-15 seconds then give it a rest for another 10 seconds and try starting again. I do have the throttle up at about 2/3 open while dong this. Usually after 4 or 5 times of cranking it for 15 seconds it will start and run rough until it burns off the excessive fuel then it runs great. I absolutely hate doing that because I know I’m killing the starter.
Just replaced the starter, the old one worked but it was on its way out
 

HiCrestRick

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Rick Wilson
Another thing it could be is oil pressure, if it has a oil pressure switch and you are using a multi grade oil. Such as 5w30 mobil 1 like Briggs and Stratton recommend it could be the oil is thinning out when it gets hot. Talk to your local small engine mechanic, ask what oil they use in Briggs motors. I'll bet it is straight 0w30. I put 0W30 Mobil 1in my customers Briggs motors and have never had problems. Just serviced on this past week with 4200 hrs and still running. Just something to look at.
Pretty sure it's straight 30w
 
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HiCrestRick

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This is Scott With Legend Brands, Has the fuel filter with the return been changed recently?
sounds like too much fuel is getting to the carb, is the choke sticking? Fell free to contact me at 866-445-3030 ext 4007
I'll check it out, thanks
 

JDARNOLD

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Yes straight 30w synthetic. Here in North Carolina with the heat the 30w works better.
 

Ara Klujian

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Popping out the carb is pre-ignition. That's not cool. Especially if it was hot.Were you turning it over for a long time? Usually it bangs out the exhaust.
 

HiCrestRick

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It seems to be much better now, I'm not sure why, and no, I didn't crank it for long, if it doesn't fire right back up I usually will walk away for five minutes or so. But that problem seems to have gone away, maybe I was doing something different and not realizing it...
 
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