# Troubleshooting fuel smell, can't quite find the source, Tecumseh engine



## SweetD (Dec 6, 2013)

Hi Everyone,

Towards the end of last season I noticed a pretty strong fuel smell coming from my snowblower, to the point that I had to leave it outside rather than in the garage. I put it away for the winter assuming I had a cracked plastic fuel tank or a cracked fuel line.

Fast forward to today, where I spent a couple of hours pulling the blower out of the shed, changing oil, greasing and oiling, etc. to get her ready for the season. I pulled the fuel tank off the unit and inspected it - it has a couple of what look like small superficial cracks (pictured below) right where the stiffening ribs meet the mid-tank seam. I noticed the cracks last year and assumed that was my fuel smell source.

Well, I filled the empty and dry tank with water today and watched for any water leaks - nothing. Only when I put the tank upside down with the cap on, some water came out of the cap. Is the cap supposed to be air/fuel tight, or is it vented?

So I suppose the small cracks I can visibly see could be leaking fumes and not fuel (or water), but I find that unlikely? I also inspected the entire fuel line from tank to carb and could see no cracks or leaks in it today. I have never replaced the line myself, but I can tell it has been replaced before and seems in good shape.

Any ideas or experience with those small cracks on my fuel tank? Anyone have the same sort of thing happen? Hate to buy a new tank if that's not the problem. Maybe I should try sealing the cracks up anyway with JB Weld for plastic? Here are a few pics:










































Thanks!

Dave


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## Normex (Feb 21, 2014)

With the winter and first snowfalls looming I would not fool around and get a new tank. Just my opinion.


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## Shryp (Jan 1, 2011)

Those Tecumseh tanks are all the same. Check your local craigslist or a local repair place and I bet you could find a used one for cheap.

The cap is suppose to be vented.

Temperature and pressure can also have an effect on those cracks. The warmer the plastic is the more the cracks will expand. Also, if the gas swells up the pressure can push on the inside of the tank, though the vent should stop that. Maybe some of the vents have 1 way valves to let air in, but lot let vapors out? Ever see what happens to a plastic gas can when it heats up? They can look like balloons.

Tanks can be fixed with a 2 part epoxy, or a soldering iron.

If the needle and seat in the carb are leaking all the gas can leak out of the choke of the carb as well. Some engines it will leak right into the cylinder and then the crankcase oil.

If the fuel line was replaced incorrectly, the flywheel could have rubbed a hole in it behind the engine cover.

If you want to cover all bases you could also add a fuel shut off valve under the tank.


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## BullFrog (Oct 14, 2015)

+1 
I can't say for sure if what I'm looking at in the photos are cracks or scratches but if I had doubts I'd just replace the tank and be done with it. To try and seal it effectively the tank would have to have a lining applied to the inside of the tank. As for the gas cap I'm not sure. It may be vented for atmospheric pressure.


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## SweetD (Dec 6, 2013)

Shryp said:


> If the needle and seat in the carb are leaking all the gas can leak out of the choke of the carb as well. Some engines it will leak right into the cylinder and then the crankcase oil.


Thanks guys for the feedback.

Shryp, what would any symptoms of the condition you mention above be? I changed the crankcase motor oil today and it was dirty but not gunky(one season of use), and didn't seem like any fuel/oil was separated in it.

While operating the machine, obviously gets warm/hot during operation around the motor. I have noticed some sheen to the melted water that sort of sits on top of the motor around the plug area, like little pools of melted water with an oil/gas sheen. I just assumed it was exhaust combining with the melting snow/water, etc. Does that seem normal?

I am familiar with carb rebuilds/replacements with outboard motors, so I could tackle that myself...but my blower seems to run great, no stalls, no surges, just keeps truckin'...

Thanks again,

Dave


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## nwcove (Mar 2, 2015)

i would replace the fuel line, primer line and primer bulb also. ethanol takes its toll .


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## Shryp (Jan 1, 2011)

If the gas leaked out of the choke you would see a lot of gas next to the machine on the floor and the tank would empty itself. If it was leaking into the oil then the oil would smell like gas and be way over filled.


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## SweetD (Dec 6, 2013)

nwcove said:


> i would replace the fuel line, primer line and primer bulb also. ethanol takes its toll .


Good call, I didn't think about the primer line and bulb!

Thanks,

Dave


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## SweetD (Dec 6, 2013)

Shryp said:


> If the gas leaked out of the choke you would see a lot of gas next to the machine on the floor and the tank would empty itself. If it was leaking into the oil then the oil would smell like gas and be way over filled.


Ok thanks, I'm not experiencing those symptoms (at least!) - !

Dave


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## SweetD (Dec 6, 2013)

*Update*

I have an update to this thread - got the new fuel tank installed today. 









I had taken the carb apart for inspection a couple of weeks ago and it seemed "fine" overall, so I just put it back together. Very clean overall.

Fresh fuel and oil, fired up on the third pull (first time starting this season), and ran without a hiccup for ten minutes. Put it through the gears and auger and it all worked great.

So hopefully that new tank fixes the fuel smell. If not, I will probably rebuild the carb just to eliminate it as a possibility. Not sure if it's ever been rebuilt anyway, certainly not by me!

Bring on the snow! 

Dave


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## brickcity (Jan 23, 2014)

guess you don't smell gas?
good job.


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## SweetD (Dec 6, 2013)

brickcity said:


> guess you don't smell gas?
> good job.


Roger that - not yet anyway! I do have a fuel shutoff valve in-line...


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## 94EG8 (Feb 13, 2014)

SweetD said:


> I filled the empty and dry tank with water today and watched for any water leaks - nothing.


Don't check fuel tanks that way, for a couple of reasons:



Water molecules are a lot larger than gasoline, it the plastic is damaged from UV exposure and crazed water wont go through, but gasoline may very slowly work its way through over time.
It's a royal pain in the ass to get all the water out of the tank. All you need is a few drops of water to cause you grief all winter.
Bottom line: Use gasoline to check for leaks.


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## SweetD (Dec 6, 2013)

Interesting, I have read that lots of people use H2O to test tanks for leaks - but that doesn't mean it's correct of course. Thanks for the heads up.

In any case, I'm trashing that tank and using the new one, so no harm no foul this time I guess - !

Dave


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## Sylvain Pelletier (Feb 10, 2018)

*Gas smell in garage*

I bought a Snow Tek snow blower 3 years ago and last spring I ended with gas smell in the garage with no visible leaks. Had to run it dry every time I used it to avoid gas smell each time. A maintenance guy recently change the oil, cleaned it all up and couldn’t find any possible leaks. Brought it back and now I still have the gas smell in my garage. Will need to run it dry again. Anyone have the same issue? Any thoughts on this would really be appreciated. :sad2:


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## tadawson (Jan 3, 2018)

Is there a shutoff valve? I've had those slow drip . . . Barring that, it's tank, hose, float valve seat/needle/float . . . . nothing else is wet when not running . . .


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