Weed trimmer ( Weed Wacker ) not starting?

[Don2222]

Hello
I have Sears Craftsman Weed Eater that is not starting now but worked the last time I used it.
After cleaning the air filter and changing the spark plug and trying some starting ether it still was a no go. So I took off the black plastic cover to the back side of the engine and tried pulling the starting rope handle. Then part 35 - The electric start cover fell off! So I put it back on and reassembled it and low and behold the weed wacker started right up with only one pull!
It worked for about 5 mins and gave a jerk and shut down. Now it will not start again so I took it apart and found damage to the part 4 - the O ring seal that seals the cover to the engine! Now if this seal leaked and causes the normal approx 90 PSI to drop down to 50 PSI or below then the engine will not start!
So my question is?
Will a new O ring or maybe some high temp RTV seal this up so the weed wacker works like new again and starts with 1 or 2 pulls???

Lawn & Garden Equipment O-Ring 753-06174 parts | Sears PartsDirect

Lawn & Garden Equipment O-Ring 753-06174 parts - manufacturer-approved parts for a proper fit every time! We also have installation guides, diagrams and manuals to help you along the way!

www.searspartsdirect.com

Not sure if it is worth spending $2.46 or just try high temp RTV??
Pic 1&2 - Craftsman weed trimmer similar to many other brands too!
Pic 3-4 - Damaged O ring seal
Pic 5-8 - owners manual shows weed trimmer model # 316-711190 and O Ring part # 753-06174
Pics 9-12 - More pics of removing back plastic and electric start cover removal.
Note: There is a different Craftsman model of this weed wacker that has a plastic cover which can get damaged and leak air. My weed wacker has a heavy metal cover but I believe the O Ring seal can get old and leak which will also cause low compression.
See similar problem on a different Craftsman model weed wacker here

To view this content we will need your consent to set third party cookies.
For more detailed information, see our cookies page.

Accept third party cookies

 

[EatenByLimestone]

I dont think RTV will hold the compression.

 

[Don2222]

I dont think RTV will hold the compression.

I ordered some O rings so we will see if this will fix it?

 

[Sodbuster]

How old is this trimmer? We are in the age of throw away models in some instances.

 

[Sodbuster]

The reason I ask is many of the home owner models are built for a specific number of hours, after that you are on borrowed time. Let us know what you find out.

 

[Don2222]

The reason I ask is many of the home owner models are built for a specific number of hours, after that you are on borrowed time. Let us know what you find out.

I am not sure of the age maybe 3-4 years but not used very much. As I said earlier In my post that when I took it apart and put it back together it started in just one pull!
Therefore it must be something very simple! So it is not very old or used and I was hoping that someone else had the same issue and knows the answer. Have you seen this issue,
I waited for the O ring to come and that was not the fix, but still very suspicious there is an air leak and not enough compression to start it??

 

[Sodbuster]

Here's what I would try.

1. Make sure you have spark, new plug does not equal spark, and make sure it's a strong spark.
2. Make sure your carb is squeaky clean blow out all the orifices with carb cleaner followed by compressed air. Make sure the fuel filter is
clean.
3. Get some Permatex Ultra Gray and lay a small bead on the flange where the O-ring sits, them embed the o-ring in the
Permatex. Then lay another small bead on the other mating surface, and tighten everything down. Let the Permatex cure for 24 hours
and give it a go.

It could be as simple as a bad ignition switch, but I doubt that.

 

[mustash29]

A lot of the "big box store" small engines are designed to be throw away. They are just not built to last. One of the contributing factors is the fact that they are tuned extremely lean from the factory in order to meet emissions limits. They build them with these stupidly shaped adjusting screws on the carbs to keep most folks from messing with them. It's amazing how well a POS will run if it is tuned ever so slightly richer.

I have a 27 cc Troy-bilt that was free. It was essentially brand new but someone threw it away because it started and ran like crap. After adjusting the carb it screams now. It drives my 12" tiller attachment with a vengeance and make quick work of fluffing up the flower beds each spring. I only use it occasionally for trimming or tilling so I feed it with canned "true fuel" to eliminate the ethanol / premix issues.

If you don't already have a kit like this in your toolbox you need to get one ASAP.

Amazon - HIPA (Pack of 10 Carburetor Adjustment Tool + Carrying Case + Cleaning Bursh for Common 2 Cycle Small Engine Echo STIHL Poulan Husqvarna MTD Ryobi Homelite Trimmer Weed Eater Chainsaw