# Ryobi 790r Primer Bulb



## The Hozer (May 25, 2006)

Hello I'm new to this forum and new to 2 Cycle Repair as well.

I have had my Ryobi 790r for about 12 years and it has worked fine until about a couple of months ago. The engine would stop working when it got to hot.

Not knowing how to fix it, I was going to buy another one, but a friend of mine (who had the same model, but curved shaft) gave me his, as he bought a newer more powerful model.

Well, his worked O.K. for about two months then it wouldn't start anymore. That's when I noticed that the Primer Bulb wasn't getting filled with fuel. I went back to my trimmer and noticed the Primer Bulb wasn't getting fuel also!

A diferent friend told me that it was probably bad fuel and instructed me to drain the tank and refill it with clean fuel. He also reccommended that maybe I should try using staight gasoline and start the engine for just a moment to try and clean out any junk the the motor, carb, and spark plug.

Well I tried that last night (the pure gas trick) and the Primer Bulb filled up twice and then it wouldn't get aymore fuel and the engne didn't start.

So I'm back to square one, I read a thread about possibly soaking the carb in cleaner and I wanted to get the forum's opinion before I do that. Am I barking up the wrong tree with this or not?

Sincerely,
The Hozer


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## hankster (Jan 1, 1998)

The primer bulb in most cases will not fill up completely. Never ever run straight gas in a 2-cycle motor. I would guess the carb has gotten slightly dirty making the engine run lean, try opening the mixture screws on the carb 1/4 to 1/2 turn.


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## The Hozer (May 25, 2006)

Hello Hankster,

I tried opening up the mixture screws, but that didn’t work.

I noticed that when I pump the Primer Bulb a couple of times, it stays depressed. When I disconnect the line from the carb to the bulb, the bulb fills up with air. I checked all the fuel lines and they seemed to be clear. This makes me believe that there is something clogged in the carb.

From what I have learned on the forum, I have a Walbro WT275 Carb. My local lawnmower shop had a replacement Walbro primer bulb, so I bought one because the one on the trimmer was starting to crack and for $5 I figured why not, but it didn’t resolve the problem.

So what do you think I should do next?

I’ve read on the forum, that you can rebuild the carb and my shop has the kit, do you think I should try to do rebuilt it or is there something else I should try first?

Do I need special tools to perform the rebuild?

Thanks, 
The Hozer


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## hankster (Jan 1, 1998)

If the primer is sticking then most likely the carb will need to be torn down, cleaned and rebuilt. Might as well replace the fuel filter while you are at it.

Rebuilding if fairly easy, soak in overnight, blow it out and replace all of the gaskets and diapharm.


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## The Hozer (May 25, 2006)

Thanks Hankster,

There are two kits for my carb. The K10-WAT and the D10-WAT. My guess is that the D10-WAt is just the diaphram and the other has everything including the adjustment screw and seats?

Which kit do you recommend I get?

Also, the fuel filter for my Ryobi doesn't seem to be repalceable, am I wrong about this? If I am wrong, do you know where I can buy some?

The Hozer


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## hankster (Jan 1, 1998)

Not sure on the kit numbers as I normally don't use kits for a rebuild... just take parts and pieces to replace what is needed  I would guess the more expensive kit has more parts 

Yes, the filter is replaceable. Anyone that sells Ryobi/MTD parts should have them available. One example is Sears at http://www3.sears.com


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