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Lawn Boys Never Die
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2,049 Posts
Discussion Starter · #1 ·
A co-worker gave me an MTD with a briggs engine for free. He said it would not start. It is a briggs 4.5 with a primer on the carb. So I prime it and nothing happens, no spurting fuel.
I pour some gas in the carb and it starts on the first pull and then dies. I pull the carb apart and its clean as a whistle, no obstructions. I go to put it back together and its kind of a pain. I get to looking at it and I find that the plastic intake manifold is broke in half. Ok, no biggie, I already found one on e-bay for cheap.
My question, being a newbie, is the broke intake manifold causing my no prime issue?? Do I have a massive air leak which is causing the no prime issue. I checked the primer bulb and and it seems to be functioning, I can hear air being forced out when I press it, but it is not drawing gas into the carb. :banghead3:banghead3
 

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Lawn Boys Never Die
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2,049 Posts
Discussion Starter · #2 ·
Think I got it figured out. Looks like the diaphram is shot. Did a little research and narrowed it down to this.
 

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Registered
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569 Posts
How does the Diaphragm look (Gasket Between the Carb and Tank).
They are cheap, couple bucks.

The fuel pickup tube is clear? Nothing blocking it?
 

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Lawn Boys Never Die
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2,049 Posts
Discussion Starter · #4 ·
How does the Diaphragm look (Gasket Between the Carb and Tank).
They are cheap, couple bucks.

The fuel pickup tube is clear? Nothing blocking it?
Fuel pick-up tube is clear. Diaphram is coming apart and torn.
 

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Lawn Boys Never Die
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2,049 Posts
Discussion Starter · #5 ·
Update, with a new diaphram the primer is working perfectly.:thThumbsU I tried to use the busted in half intake manifold, no go!! Will ony start with gas poured down the carb and then barely. :banghead3 Just ordered a new intake manifold.
 

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4-Stroker
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68 Posts
They are pretty easy to do. Sounds like you are on the right track if there is any breakage or crack in the plastic intake tube.

Let us know if you have problems after you install the new part!
 

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Young Buck
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1,611 Posts
I have had alot of trouble with briggs older diaphragm carbs, especially finding new ones. I have one that dumps fuel when shut off(don't use but is to nice looking to toss) and one that needs too be primed with ether to get it going. on Most of the briggs that I have worked on the primer is part of the air cleaner back plate, and the gasket for it always needs replaced.
 

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on Most of the briggs that I have worked on the primer is part of the air cleaner back plate, and the gasket for it always needs replaced.
Yup. The primer gasket is the most stupid designing I ever see :sorry1:
 

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Resident Man Of Many Hats
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2,641 Posts
Those diaphrams are notorious for coming apart. Good thing is they are super cheap and take all of 5 minutes to replace.
 
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