# UH OH- Straight gas in a 2 cycle



## Docsab (May 6, 2009)

My apologies if this is an old subject, but my search failed to find a similiar thread. My father(early alzheimers) put straight gas in my craftsman single stage 2 cycle snowblower and ran it until it stalled.

I, horrified, changed gas, cleaned carb and cylinder, put in new spark plug but not even a sputter. Is it worth bringing to a repair shop or do I just consider this engine fried??


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## luckyvision (May 24, 2007)

do some basic checks, change the plug since it's probably burned, pull the exhaust & check the cyl for scoring & check compression.

Since it's not locked up, that's good. I've had some luck carefully cleaning scratches off the piston & replacing the rings & base gasket. they usually will run well enough to use in those situations, just not at the performance level like they were new. your biggest investment will be time.


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## 30yearTech (Sep 14, 2006)

Very unlikely that there is anything wrong with the spark plug. Do as suggested above about taking a look at the cylinder and piston. It depends upon how extensive the damage to the cylinder and piston, if it will be a cost effective repair or not. Post the engine brand model and spec numbers if you can.


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## luckyvision (May 24, 2007)

yeah, the plug might be ok, but if it's not you could repair it but still not have it run right &then you'll think you wasted your time & money... a plug is $3 bucks. toss it!


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## Docsab (May 6, 2009)

I replaced the plug. Engine is not locked up. I don't have the tools to check compression, but from what I gather from your comments, might be worth having someone with the correct tools to check it out. Why do these things always happen when a monster snowstorm is bearing down on you?? (philadelphia burbs)


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## 30yearTech (Sep 14, 2006)

luckyvision said:


> yeah, the plug might be ok, but if it's not you could repair it but still not have it run right &then you'll think you wasted your time & money... a plug is $3 bucks. toss it!


Unmixed fuel in a 2 cycle engine won't kill a plug, in fact it's far more likely that the oil mixed in the gas will cause a plug to fail. The spark plug likely is not the problem! If the compression is good and the cylinder and piston look alright, your getting fuel and spark and it still won't start, then try a new plug.

Yes, it may be a good idea to have someone with the proper equipment check the compression. You can tell a lot from a visual inspection of the cylinder and piston through the exhaust port.


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## luckyvision (May 24, 2007)

I'm not disagreeing with you 30yr, my point is just if the cyl got hot from straight gas, that stresses the plug, better to just eliminate it from the equation. the old plug can allways go back in if the machine is otherwise ok.

30 Yr: mechanic A & Mechanic B eh?, lol


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## justin3 (Apr 10, 2007)

Its more likely the Cylinder got tore up, or the rings froze to the piston, even more likely if it was a Tecumseh engine


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## 30yearTech (Sep 14, 2006)

luckyvision said:


> I'm not disagreeing with you 30yr


Ah... yes you are, but that fine. There is nothing wrong with a difference of opinion.




luckyvision said:


> my point is just if the cyl got hot from straight gas, that stresses the plug, better to just eliminate it from the equation. the old plug can allways go back in if the machine is otherwise ok.
> 
> 30 Yr: mechanic A & Mechanic B eh?, lol


I am saying that the extra heat from straight gas *WONT* damage the spark plug, before there is damage to the engine itself. The extra heat is generally concentrated in the piston (more specifically around the exhaust port), causing the piston to expand and bind in the cylinder. This along with the lack of lubrication, causes the scoring on the piston and cylinder, but does not affect the plug much at all. Sure plugs are cheap, and I would replace it, if I thought that was the problem. The problem from running a 2 cycle engine with no oil is more serious then a spark plug, and unfortunately a new plug is not going to fix this. If the engine is rebuilt or short blocked then I would also recommend a new spark plug. 

I guess the point I was trying to make, is for the poster to do what you initially suggested. Check the engine for damage and check the compression, as the plug is not likely the reason the engine will not start.


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## Docsab (May 6, 2009)

30 yr- Thanks for the explanation of how straight gas damages an engine- I'm not feeling too gad about the prospects of my engine now. I'm having someone look at it- I'll keep you informed.


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## newz7151 (Oct 15, 2006)

luckyvision said:


> I'm not disagreeing with you 30yr, my point is just if the cyl got hot from straight gas, that stresses the plug, better to just eliminate it from the equation. the old plug can allways go back in if the machine is otherwise ok.
> 
> 30 Yr: mechanic A & Mechanic B eh?, lol


Go back up to the original post and start reading at word 47.


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## Homer D Poe (Jan 6, 2004)

have nutbars using straight gas on equipment all the time, have had a 50/50 luck in using a lil TLC to fix them with out major expense. Carefully polishing score marks on cylinder and freeing piston rings and cross all fingers.


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## Docsab (May 6, 2009)

Thanks for the encouragement Homer. Although I wouldn't consider my father a nutbar, just a little demented.


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## nnyparts.com (Dec 28, 2009)

Just to add to what has already been posted....if its your piston/rings or cylinder wall, you have to figure first what the snowblower is worth if everything worked. I have seen people spend 400.00 on a machine you couldn't sell on a good day for 200.00 Most shop rates now are over 60.00 an hour plus the parts.

Sometimes we have to bite the bullet and go buy a new one that has a warranty. I always say things happen for a reason...maybe your dad is trying to tell you something


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## Lawnmowertech (Nov 12, 2008)

nnyparts.com said:


> Just to add to what has already been posted....if its your piston/rings or cylinder wall, you have to figure first what the snowblower is worth if everything worked. I have seen people spend 400.00 on a machine you couldn't sell on a good day for 200.00 Most shop rates now are over 60.00 an hour plus the parts.
> 
> Sometimes we have to bite the bullet and go buy a new one that has a warranty. I always say things happen for a reason...maybe your dad is trying to tell you something


my shop dont charge that much a hr in the 22 years i been doing this i never exceded above 48 a hr most time i dont even charge by the hr just the job what i think its worth most folks fix there own equipment with that said if its sentimental value to the customer they are going to fix it regardless of what others tell them besides why buy something made in china compared to american made products from the 80s and 70s that when fixed will last more than 20 more years ?

Think of value think of quality of the product yes i fixed homelite vac attack blower once for a customer brand new lasted only 2 weeks even with a short block overhaul 

comes to show you if its not made on american soil chances are it wont last a year 

30year will agree with me and so will some others American made products last longer anyday


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## nnyparts.com (Dec 28, 2009)

I didn't say all shops charge that much. Actually we charge between 30 to 36.00 depending on the job ahead of us because our customers in our area don't have deep pockets. We are an authorized Briggs, Honda, Ariens, MTD dealers...the list goes on and I have been personally told by the company reps to raise my shop rate to at least the going rate of 60.00 an hr.

All warranty work is billed at a minimum of 60.00 hr and some allow up to 75.00 depending on what my mechanics are doing. I have two full time mechanic covering everything from small engine repair right up to 60 hp tractors.


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## luckyvision (May 24, 2007)

Seriously, you actually took time to count words, lol? 




newz7151 said:


> Go back up to the original post and start reading at word 47.


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