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6.5 Briggs Fuel in crankcase

2K views 17 replies 9 participants last post by  APinNY 
#1 ·
I have a Troy-Bilt 3250w generator with 6.5hp Briggs that was leaking fuel out of carb, and into crankcase.

I drained crankcase, let it air dry for 2 days and replaced needle valve /seat.

That did not solve the problem.

I then replaced the carb, drained and refilled with oil again.

Same problem.

What are the next steps in troubleshooting this problem ?
 
#3 ·
In looking up that model Troy generator it shows having a fuel shutoff under the tank from the factory. You might pull the hose off at the carb and make sure the valve really is cutting off fuel flow when off.
Have you check the float level of the old carb after replacing the needle and seat and of the new one ? Just because it's new doesn't mean it was set up correctly.
Just hard to imagine that much gas getting into crankcase.

.
 
#6 · (Edited)
Generator does have functioning shut off valve.

I replaced fuel line when I replaced carb.

Pic in previous post is the generator. with 900series 6.5 Briggs

Engine model is not readable,as it is engraved/stamped on the heavily rusted ohv/rocker cover.

I tried for hours to read,research,contacted Troy-Bilt, Briggs etc.

Tried to remove rocker cover, and was so tght I fearded bending it trying to remove.

Finally found a video on youtube of a guy repairng a gen exactly like mine that had been sitting a long time.

He replaced carb as it was severly fouled up from corrosion.

Luckily he put a link to dealer with carb model number in the video.
 
#7 · (Edited)
Is there a anti backfire solenoid coming in at the bottom of the carburetor bowl?...If there is you would see a wire going to the bottom of the carb bowl...if that is present it is not working properly......if you drain the gas and unscrew the fitting you should see the piston ride out and in when the key is switched back and forth if it is working. This is not an uncommon problem on gravity fed system......if it does not work....either replace it, or as suggested, install a shut off valve in a convenient place and don't forget to use it
This is from a kohler...but it would look something like this
 

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#11 · (Edited)
I know what it is for, ..as name implies, it is supposed to prevent backfiring by cutting off fuel supply from the bowl within the carb when key is turned off but if it does hang open it can allow flooding...kind of grasping for a solution

Usually the needle valve and its seat causes it...but OP says he changed that...I just wonder if he put seat in upside down....or if the float is not "floating" for some reason
 
#14 ·
I know what it is for, ..as name implies, it is supposed to prevent backfiring by cutting off fuel supply from the bowl within the carb when key is turned off but if it does hang open it can allow flooding...kind of grasping for a solution

Usually the needle valve and its seat causes it...but OP says he changed that...I just wonder if he put seat in upside down....or if the float is not "floating" for some reason
If the antibackfire solenoid pintle hangs open it won't cause the crankcase flooding. The gas is getting past the carb float needle and seat.

I've purposely cut off the pintle needle end on antibackfire solenoids so as the carb could be used on a non- 12v engines.

Can you explain how you think a antibackfire solenoid hanging open would be the primary reason for crankcase flooding?
 
#13 ·
Right: gas is still getting past the Carb floats needle and seat. I've seen engines run and operate ok with just a seep or slight leak because the gas was being consumed by the engine. Kill the engine and sometime later the crankcase MAY flood. Sometimes it's intermittent and erratic. If the engine runs and operates ok just install a fuel shutoff and move on.

This is why gravity fed fuel systems need a fuel petcock.
 
#15 ·
On a side note fellows the afterfire solenoid do not operate the same as mower engines. It activates on shutdown until the generator is fully shutdown then it re-opens. On mower engine when activated it retracts, on generators it extends.

As mention it would the needle valve, the seat, or both that causing the leaking. A hang float does it too. Clean carburetor again, invert it for bench testing, and do leakdown test it should hold 7-10 psi air pressure inverted with just the weight of the float operating the needle valve to seat contact.
 
#17 ·
Mark,

Posting on forums can hazardous to your mental health at times. I have had my head nearly bitten off by posters at times. Some rather bite the hand that tries to help at times. It is one of the reason I seldom post on this and many other forums trying to correct known erroneous information. I have simply quit several forums on the account of bad actors. Plus a lot of my requests for help does goes ignored.

What everybody got to understand not all of the members are experts. Some simply don't the experience that some us that have been doing repairs for 40 yrs. Even us old dogs need to learn something new. Try working a fuel injected UTV with electrical problems and don't know the OEM had intentionally put in a limp mode if the hand brake is engaged. Even the local Bobcat and Polaris dealers didn't know about this one. What worst is it is only mention in the owners and service manuals under parking braking adjustment. I was basically getting ready to have the owner take the UTV into the Bobcat dealer fr repairs when we discovered it.

Plus there are many so called techs out there that don't even know what they are doing. I had local DIYer here thought just any old safety switch would work and when it didn't he jumper other switches and return the customer mower. After the customer was mowing, got knock off his mower by tree limb, and the mower continue on taking the side of his new car he brings in the mower to me to find out what was done to it. The court case is still pending.

I am one those techs that hate getting in fuel solenoids that have been clipped just because it was dirty and hanging.

In this thread since the engine model and type numbers wasn't posted there is not a lot I can suggest as I don't know the setup other basic carburetor service procedure. It is like guessing which I don't like doing.
 
#18 ·
For the most part this is a friendly place, and we aim to keep it that way. When a discussion turns into an argument and folks get edgy it is time to close the thread.
 
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