Briggs 4 stroke help

[mikefunaro]

To the mods: if this belongs in the "off topic" forum feel free to move it. I feel as though it is at least tangentially related to chainsaws/the motor aspect and would like some engine oriented minds to see it.

I have an engine like this on a 5hp little wonder blower. It doesn't have the gokart exhaust but you get the idea

In past seasons it's started with a few pulls on choke regardless of how long it sits. It's gotten to the point that it is very hard, if not impossible to start without starting fluid. If I take the air filter out, and spray for like 20 seconds, it starts and turns over and runs very strong like it always has.

What am I looking at here? A carb kit? If it does run just fine I assume it cannot be the plug...unless could the plug be sparking weak at this point?

Let me know what you think..

 

[BloodOnTheIce]

Those motors have a diaphragm in the carb, they wear out after enough years of use. Drain the tank & clean it, replace the diaphragm, put on new tank gasket, then you should be good to go.

 

[mweba]

Those motors have a diaphragm in the carb, they wear out after enough years of use. Drain the tank & clean it, replace the diaphragm, put on new tank gasket, then you should be good to go.

:agree2:

Most have the diaphragm on the exterior of the carb, in between the muffler and carb. There will be a visible "cap" with four-five screws. Kit should also come with a spring. Cleaning the tank is a good idea but not necessary if it looks good. Last tank of fuel I run through these for the year, I add just a little oil mix. Keeps the metal tank from corroding.

 

[mikefunaro]

BOTI, sent you some rep, Mweba, it's a bit too soon for you in particular according to the system

Thank you both very much!

 

[lawnmowertech37]

Diaphragm is most likely brittle it is on the side of the carb do not really have to remove the carb from the engine to change it just remove air filter

just be careful not to lose the screws and the spring inside that area

 

[mikefunaro]

Calvin are you likely to have this stuff in stock? I will get you a model type/number in a bit!

 

[Sprintcar]

Mike,

Since you are going to put a carb kit in this motor, pull the starter housing and look at the magnets in the flywheel. If these motors are used in a damp or wet enviroment these magnets and the legs on the module will become corroded and will rust over. The engines will run, but are a :censored: sometimes to crank. Use a piece of emery cloth and cleans the magnets and the legs on the module.

Good luck,

Jerry

 

[bcsizemo]

Just my .02 cents...

I'm sure everyone is right on the diaphragm...and that engine looks very familiar to the one on my go kart when I was a kid.

Either way it was a real PITA to start. I switch out the stock plug with a Champion One-Tug-Plug. I believe they call them the EZ Start plugs now a days... That alone seem to make it a lot easier.

But hell that was almost 20 years ago. I'm sure plugs have gotten better since then...I hope.

 

[Rookie1]

Check this thread out. http://www.arboristsite.com/showthread.php?t=151228 I wouldnt be surprised if the exhaust valve is "leaking"and your losing compression. Maybe do a leakdown test to see if its starting to bleed off compression.

 

[Fish]

The carbs on these sit on top of a metal tank, and they suck fuel from
the tank, and deposit in a metal bowl at the top of the tank, which is just that, the carb bowl.

If your engine runs fine after a lot of priming and pullstarting, and will
restart easily for the rest of the afternoon, but the next morning, the long
drawn out priming/pulling ritual is needed again, points to one thing.....


What is it guys????

 

[Walt41]

The carbs on these sit on top of a metal tank, and they suck fuel from
the tank, and deposit in a metal bowl at the top of the tank, which is just that, the carb bowl.

If your engine runs fine after a lot of priming and pullstarting, and will
restart easily for the rest of the afternoon, but the next morning, the long
drawn out priming/pulling ritual is needed again, points to one thing.....


What is it guys????

sediment is making the needle stay open allowing for gas to run back to tank?

 

[Rookie1]

cup has pin hole in it from alcohol laced fuel absorbing moisture from the atmosphere and rusting.

 

[Fish]

cup has pin hole in it from alcohol laced fuel absorbing moisture from the atmosphere and rusting.

Yes!!!!!

Absorbed water has set in the bottom of the cup and rusted pin holes in the
cup.

You win a cookie!!!!!

I have layered some JB weld in and it has held pretty well.

 

[Rookie1]

A cookie. I thought Id get a little more. Oh well at least I won.
Anyway keep us posted on the outcome.

 

[lawnmowertech37]

Calvin are you likely to have this stuff in stock? I will get you a model type/number in a bit!

Have both on hand

 

[tallfarmboy]

One other thing to look for... the majority of the 5HP Briggs that we work on in the ag shop here at school have a plugged intake tube... either the long tube OR the short tube. I have seen a couple this year that we had to get a straight pin and hammer it through the plugged up crap in the tube. Carb cleaner wouldn't open it up, but the straight pin did the trick.

 

[HimWill]

The easiest way I've found to "work around" the leaky fuel bowl is to tip the engine to the side and "prime" the bowl.Works on mowers,maybe your blower can be "man-handled" too.(Really hard to do on a wood splitter.)

 

[WVshooter]

The easiest way I've found to "work around" the leaky fuel bowl is to tip the engine to the side and "prime" the bowl.Works on mowers,maybe your blower can be "man-handled" too.(Really hard to do on a wood splitter.)

If you can do that with your wood splitter, you probably don't need a wood splitter.........

 

[abikerboy]

Another thing, if the fuel cup has a pinhole, if you fill the tank to the top, then it will start easy. The cup is open partially on the side, so a full tank of gas will fill the cup. I have a chipper with a briggs on it that has this problem. Also, the daphragm, there are two styles depending on whether it has 4 screws or 5. If I remember correctly, you can use the 5 hole diaphram on the 4 hole carb, but not vise-versa!