Blower primer bulb not getting fuel into cylinder.

[trouts2]

Blower is a Homelite Vac Attack, model UT-08542.
The blower was in my camp attic for maybe 5 year and forgotten about. I think I likely put it away with no gas.
I'm now trying to get running right.
The primer bulb was cracked. If I put gas in through the filter it starts and runs fine for a short time.
I took it apart, put on a new primer, put on new gas lines and a new tank filter.
The new primer is an assembly with a new bulb. There are two ports on the primer. One is short and the other long. The short one has the "in" marked.
I tested the primer with two lines. One went to a cup of water and the other just dangled. When I pushed the bulb it sucked water into the bulb and pushed out water out of the long port so I think it works fine.
I ran the short port line to the side of the carb port opposite from the line from the tank. I ran the long port line into the tank. When I pump the bulb the bulb fills with gas so I thought it should work. The blower would not start. With many pulls and bulb pumps it should start. It did not start. I pulled the plug and it was dry. After a lot of pumps and pulls I would think the plug should be soaked with gas but it is dry. If I put gas in through the air filter it starts fine and runs fine so gas can be sucked out of the tank by the carb.
The new primer and lines I think are connected right but something is wrong as priming does not get gas into the carb to start with. ??
I think the carb probably has a couple of diaphragms inside and they are probably ok as the engine runs fine.
At this point I'm not sure what to look for. What would stop the gas from getting suck into the carb via the primer action?

 

[Opelman]

Diaphragm on the metering side might be stiff and not allowing the fuel inlet needle to open or sitting that long the needle might be stuck not allowing fuel flow. Let it sit overnight and see what happens. You might get lucky.

 

[trouts2]

Diaphragm on the metering side might be stiff and not allowing the fuel inlet needle to open or sitting that long the needle might be stuck not allowing fuel flow. Let it sit overnight and see what happens. You might get lucky.

When I ran it, it ran very well and idle to fast response seemed fine. I think the bulb suction uses parts of the carb that are used in normal running but that is a guess as I don't know the internal paths. I ran it a lot today and see if any change tomorrow. If nothing I may just get a replacement carb which I think is $14. I think the issue has to be something carb internal. I put some carb cleaner sprays in the carb holes but did not take it apart which I should have done.

 

[jhellwig]

The primer usually only pulls fuel through the pump side of the carb on 2 stroke stuff. It does not put fuel into the intake. There should still be a choke that you have to close to get a slug of gas to come out of the carb to start it.

 

[trouts2]

The primer usually only pulls fuel through the pump side of the carb on 2 stroke stuff. It does not put fuel into the intake. There should still be a choke that you have to close to get a slug of gas to come out of the carb to start it.

Closing the choke does not get gas up to the cylinder. If I pull the cord many time with the choke on it never floods. If I prime many times and pull to start then go back an forth priming and pulling the plug does not get wet.

 

[trouts2]

Opelman,​

jhellwig, your comment was particularly helpful. I have worked on many two stroke carb internals and replaced primer bulbs and gas lines before but your comment made me realize that I never understood >>how<< the gas floweded with priming. I stopped working on the blower to bone up on the internal flow.



I am still a bit puzzled about once the gas is sucked into the carb where the gas goes internally to sit waiting I think from more suction due to the choke being on.



I had cleaned the original carb 3-4 times thinking that the priming action internally was messed up. Rather than rebuild it I bought on online which was cheaper.

After testing the primer action the gas lines were correct. I had good flow from the tank, through the carb and out the return into the tank so the new carb seemed fine at least for the priming and line connection part. But the engine would not start even with lots of priming. If I put gas in through the carb throat it would start and run fine.

The plug would be dry so I suspected the choke was not working on the new carb. I stuffed a rag into the throat opening and it would start. So something is not right with the choke on the new carb. When I look at the choke lever it seems so do nothing when flipped to on. By that I mean I don’t see anything happening internally in the throat. ??

As is I can used it and it runs fine but have to start it by putting the cloth into the throat. ?? The choke parts interact with parts on the top outside of the carb such that the choke arm is vertical but as far as I can tell does nothing on the inside of the throat. ??

Any suggestions about what could be going on with the choke to not get the primed gas into the throat? The gas is there but not moved by the choke. ??

 

[trouts2]

The primer usually only pulls fuel through the pump side of the carb on 2 stroke stuff. It does not put fuel into the intake. There should still be a choke that you have to close to get a slug of gas to come out of the carb to start it.

Very helpful comment, thank you.

 

[jhellwig]

Is the choke by chance part of the air cleaner cover or assembly? Sometimes it is in the air cleaner housing and when you open it you don't see it because it was on the cover. Pictures of what you are looking at would help.