Briggs Outboard Carb Adjustment

[rebelyell]

Not fouled enough to not start when I spray fuel down the carb.

 

[northcreeek262]

Why would it start 4 days ago and not now though?

I was replying to what you said earlier.

 

[sgkent]

Never noticed a welch plug in the bottom. Either it's never been there (unlikely) or it was removed by a previous owner. It's ran fine for me many seasons without it, but I guess I'll be putting one of those in this week. Might as well pull the other one and replace it too.

It's sitting in a vat of carb cleaner now.

I'd just replace it. There is so much corrosion in that carb it may never run right again,

https://www.lawnmowerforum.com/attachments/0321221806_hdr-jpg.59830/

 

[rebelyell]

Normally, yes. I would have at this point. Part is discontinued and the one on ebay "didn't idle right."

My next step is to dump it in an ultrasonic cleaner. If that doesn't work I'm going to look around for a carb body that's pretty close enough to the same and swap all the linkages over. Like this one.

 

[sgkent]

$149 canadian dollars used. He has a for all price, and then each individual part. Sounds outrageous but maybe make him an offer what you think it is worth https://www.ebay.ca/itm/292496024443?hash=item441a1f237b:g:gHAAAOSwrjhatXGR


ALSO - lots of small boat engine shops and lawn mower shops have shelves full of older parts that they don't advertise or put on online lists. Call around. That carb was used on other products. The shop near me the other day sold me some obsolete parts they had which no one else showed available. There are many busy small shops that have 20 year old inventories sitting on a shelf. But you have to call around. I'd start with the shops nearest you then expand into other towns further away. I found a part for a Mercury motor once that way, got a list of Mercury shops on the West Coast that had been around 20 years and started calling. About the 10th don't have it the guy had it and shipped it to me. Solved my problem too. Infact years later a shop in San Diego sold me a new case, crank, plates, reeds, pistons, and full carb set for it $200 that someone had ordered and never picked up. Even lent me the special tools to stuff the pistons in. Engine was like new after that.

 

[rebelyell]

I've done that a few times with other major mower parts, but carbs have usually been either superseded or in good supply. Never thought they'd have an old briggs outboard carb. I'll call around tomorrow. Thanks for that.

 

[rebelyell]

Found a carb. It doesnt have an idle mix adjustment and doesnt have an idle speed screw. Seems to be from a later model.

Installed it anyway and now it runs on choke only. As soon as you turn it off choke, it dies. Classic clogged carb. Except this one is spotless. No welch plugs to pull and all holes spray clean.

Could it be something with weak spark? Im at a loss here.

Think I might put a hose clamp on the choke where it runs fine and let it go.

 

[sgkent]

classic case of either a vacuum leak, or a bad fuel supply / fuel pump. Try spraying some berrymans around some of the fittings on the manifold and see it that changes the idle. You can use an unlit propane torch too. Or a smoke tester.

Having the choke on makes the engine pull lots of fuel. If there is a vacuum leak that makes the mixture burnable. If the fuel supply is bad, the choke may create a vacuum that pulls fuel from the tank.

 

[bertsmobile1]

Using propane to find an air leak is one thing that appears to be unique to the USA.
And when you think of it unbelieveably stupid
The combustable air fuel ratio for propane is huge
SO combustable fuel. hot engine, face close to the engine all you need is a stray spark, bit of red hot carbon or rust coming out of the muffler and you can join the very fashionable no eyebrows club
The blinded by your own stupidity club also take members this way.
It is a bad practice with car engines where the exhaust is sealed better & the mechanic is a long way from the engine.
In the government motor garage doing that is instant dismissal
Apparently it is a practice locals learned during WWII from US military workshops

 

[sgkent]

Using propane to find an air leak is one thing that appears to be unique to the USA.
And when you think of it unbelieveably stupid
The combustable air fuel ratio for propane is huge
SO combustable fuel. hot engine, face close to the engine all you need is a stray spark, bit of red hot carbon or rust coming out of the muffler and you can join the very fashionable no eyebrows club
The blinded by your own stupidity club also take members this way.
It is a bad practice with car engines where the exhaust is sealed better & the mechanic is a long way from the engine.
In the government motor garage doing that is instant dismissal
Apparently it is a practice locals learned during WWII from US military workshops

ya know, you don't have to open the propane tank full blast for10 minutes straight. Personally I used to use windex, or a tiny amount of Berrymans. Now I use a smoke generator. But if propane is all I had I would not hesitate to use it in the open air for a few seconds on low.