# Briggs 16hp opposed twin overheating/dying



## Catmaster (Jul 29, 2019)

Hi i'm having an issue with my newly acquired 16hp briggs opposed twin, it seems to be running hot to the point that it gets uncomfortable on your feet and this condition eventually leads to it running out of fuel and dying. It starts great and runs (cuts grass) strong for about 40 minutes but then slowly starts loosing power and eventually dies, the fuel filter is empty and after it cools (an hour give or take..) fires up and runs great again. I hit the fins/shrouds with compressed air and they're clean, i've changed the oil (SAE 30), plugs and air filter but it seems lean (according to the plugs) i'm running the NGK BR2LM.
From what i'm reading these carbs are non adjustable so i'm not sure how or if I can fatten it up a bit to keep it running cooler. I've also read about the fuel lines breaking down and collapsing due to the heat but the fuel lines & filter are new. Its a 3 screw carb and i haven't been inside of it yet.. The fuel cap has been drilled so I believe its got lots of venting and isn't hydro-locking. I'm not really sure where to go next..
Would a cooler plug help it run cooler?


I've got some small engine experience but have never dealt with one of these engines before so its a whole new animal to me!!
Any help or ideas would be greatly appreciated!!
Thanks

ps
Model # is 402707
Type # 0156 01
Code # 84100412


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## mrfred (Jul 5, 2011)

May have to remove the engine and clean out under the fan shroud housing, probably a mouse next or just debre stopping cool air flow. If it's a vertical engine you don't have to remove it from the tractor. Don't believe you have a fuel issue. Seen many motors with clean cooling find only to be plugged under the shrouding


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## pogobill (Jan 31, 2012)

Welcome to the forum Catmaster. I was going to mention fuel lines, but I see from your post that you have replaced them. Are you running the tractor at a high throttle? I run mine lawn tractor pretty much wide open.
Another thought is that your tractor was sold with a Kohler K341, not a Briggs, I believe. Research your Briggs and make sure that all the heat shrouds are still there. According the the Briggs and Stratton 16 H.P. twin opposed you are using one on the recommended spark plugs, although they do spec out three different plugs.
Also check to see if your drive belt is too tight, or if the deck is bunged up with clippings that is causing an undue load on your engine.


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## Catmaster (Jul 29, 2019)

Thank you for your responses! I've had a closer look since the first post and it seems the pump isn't pulling enough fuel, the filter eventually (after 20-30 minutes) runs dry and the engine will start to surge..
I am running it wide open

The Massy did come with a Kohler, this tractor is a snapper that's been converted..it has a sunstrand hydro transmission from a JD 318 and the 16hp briggs opposed twin.. 
I took a video..I'll try to post it..


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## Catmaster (Jul 29, 2019)

Apparently my video is too large to post but it shows the last little bit of fuel dissapeare from the bottom of the filter (after 20-30 minutes of grass cutting) and then you can see fuel sporadically bubbling in from the top but the filter never fills up again until the tractor sits shut off for 15-20 minutes..
I pulled the fuel cap and had no change.. I killed the engine and pulled the line from the tank off the filter and it flows freely.. I pulled the fuel line off the pump and it flows freely there too so I'm assuming theres an issue with the pump..?? 
I believe its heat related because I was able to finish the lawn and sweep it with the hood removed, tractor ran great for 2 hrs!


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## Catmaster (Jul 29, 2019)

This is how it looks on initial start up.. 








And this is after about 15-20 minutes of grass cutting..








After 30-40 minutes its empty, loosing power, surges and eventually dies..


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## pogobill (Jan 31, 2012)

Is there a fuel shut off valve.. that may be defective?
I'm also wondering if there is a shroud missing that directs the cooling air through the fins on the engine that may be missing, or wasn't required when it had the Kohler in it? You mentioned that it run well with the hood off.


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## Catmaster (Jul 29, 2019)

There is a shut off valve between the filter & pump, I played with it when I had the line off and it seemed to be working properly.. I may remove it tho just in case.. I can't see where any shrouds might be missing, theres good air flow across the heads coming out the bottom of the engine on each side.. 
I'm thinking I might cut a big hood scoop into it lol


pogobill said:


> Is there a fuel shut off valve.. that may be defective?
> I'm also wondering if there is a shroud missing that directs the cooling air through the fins on the engine that may be missing, or wasn't required when it had the Kohler in it? You mentioned that it run well with the hood off.


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## ewan (Apr 15, 2021)

hi, did you ever solve this one ? have a roper with a 16hp B&S opposed twin engine with similar issues .. runs fine for about 20 minutes then starts to lose power ... pulling choke out restores power pretty much so some kind of fuel starvation


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