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Gas splashing out of vent in cap.


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#1 IamSherwood OFFLINE  

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Posted May 21, 2011 - 06:45 AM

I'm haveing an issue with fuel splashing out of the cap vent. This is a
Tecumseh H70 w/the tank mounted to the engine.

Should there be an insert, or baffle sorta like you see the screen gizmo
in Honda engines?

If not, could there be a problem with the cap?

Thanks

#2 KennyP ONLINE  

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Posted May 21, 2011 - 06:53 AM

I seem to remember older gas tank lids having an insert that was doomed toward the tank and a small hole in it. This would let it breathe, but the fuel would run back in. Most were kind of paper like, some had a metal piece. Usually, I saw these on push mower caps.

#3 JDBrian OFFLINE  

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Posted May 21, 2011 - 07:26 AM

I,ve had this problem with several older engines that had those flat caps. You can get a new domed type cap and it will solve the problem. I believe there was a cork or rubber baffle in the old caps that let air through but stopped the liquid from coming out. They are usually damaged or missing. If you have an engine that is vibrating due to being loose or a bad motor mount, that will make it worse.

Edited by JDBrian, May 21, 2011 - 07:26 AM.
Typo


#4 IamSherwood OFFLINE  

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Posted May 21, 2011 - 10:09 AM

I,ve had this problem with several older engines that had those flat caps. You can get a new domed type cap and it will solve the problem. I believe there was a cork or rubber baffle in the old caps that let air through but stopped the liquid from coming out. They are usually damaged or missing. If you have an engine that is vibrating due to being loose or a bad motor mount, that will make it worse.


I tried with a different cap. Same. There is only about an inch of fuel. Engine is not vibrating excessively.IMO
I was suspecting that there must have been a baffle in the cap, but no longer there.
Should be a treat trying to find a new cap that fits.

#5 JDBrian OFFLINE  

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Posted May 21, 2011 - 11:16 AM

I just took a look at the cap on my MF8. There is a while plastic insert inside the cap. The centre portion of the insert is about 2/3 of the cap diameter and is about 1/4" deep
with a small hole in it. The rim of the insert goes against the top of the cap and makes the seal with the tank. I had never noticed this before? If you want a picture let me know. I'll try to get one. Sometimes you can get a new cap through the engine manufacturer. For a Briggs that I had there was a substitute cap when you looked it up in the parts diagram.
  • IamSherwood said thank you

#6 IamSherwood OFFLINE  

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Posted May 21, 2011 - 02:34 PM

I just took a look at the cap on my MF8. There is a while plastic insert inside the cap. The centre portion of the insert is about 2/3 of the cap diameter and is about 1/4" deep
with a small hole in it. The rim of the insert goes against the top of the cap and makes the seal with the tank. I had never noticed this before? If you want a picture let me know. I'll try to get one. Sometimes you can get a new cap through the engine manufacturer. For a Briggs that I had there was a substitute cap when you looked it up in the parts diagram.


My cap is exactly as you describe. Same cap as mf10 and 12.

#7 JDBrian OFFLINE  

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Posted May 21, 2011 - 03:55 PM

So you have the plastic insert in yours? I just took the cap apart and the plastic bit is made up of 2 pieces. Between that and the top of the cap is a cork ring gasket. Quite elaborate. I didn't have any gas leaking from mine before I took it apart for restoration.

#8 IamSherwood OFFLINE  

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Posted May 21, 2011 - 05:06 PM

So you have the plastic insert in yours? I just took the cap apart and the plastic bit is made up of 2 pieces. Between that and the top of the cap is a cork ring gasket. Quite elaborate. I didn't have any gas leaking from mine before I took it apart for restoration.


Thanks, I'll take a look for that cork gasket.
Did you happen to snap a pic of that gasket while apart?

thanks




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