Engine air flow issue?

I have an old B&S engine from the mid 1990s. The engine quit on me and with ether as a primer it would run for a few seconds and quit. I found an OEM carburetor on ebay and replaced the old one with the new carb.. Now the engine runs great with the air cleaner assembly removed. However, it will start to stall as soon as the air cleaner is put on the carb, even with the filter element removed. I think the carb is working fine as the engine runs great without the air cleaner. I have screwed around with multiple settings on the jet but no luck. Any help will be greatly appreciated. Thank you

Rick

Does the air filter base have a vent hole in it to match the old carb and not in the new carb? If not, it can cause this problem. Looks like an easy fix. drill a hole in AF base to match the new carb.

The carb on this engine is a pulse jet and the new carb is an exact OEM duplicate of the old. The air filter is about 3 in x 4.5 inches and the bottom has 20 holes in it measuring .25 inches to 1.25 inches. Thanks for your reply.

you did not specify the engine model type and code no.

Ooooops Engine is model 92908 5093 01 and carb is part # 395957

does the air cleaner have a breather in it that could be spewing lots of blowby, oil or water vapor?

Provomon said:

I have an old B&S engine from the mid 1990s. The engine quit on me and with ether as a primer it would run for a few seconds and quit. I found an OEM carburetor on ebay and replaced the old one with the new carb.. Now the engine runs great with the air cleaner assembly removed. However, it will start to stall as soon as the air cleaner is put on the carb, even with the filter element removed. I think the carb is working fine as the engine runs great without the air cleaner. I have screwed around with multiple settings on the jet but no luck. Any help will be greatly appreciated. Thank you

Rick

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Is the gas cap blocked off somehow? Blocked vents on the gas cap can cause this problem. It's been years since I have had an old one like this do this, but it can happen.

Gas caps on pulsa prime carbs are normally wide open. Have large holes in the cap.

Provomon said:

The engine quit on me and with ether as a primer it would run for a few seconds and quit.

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What do YOU think the engine is telling you?? It wants more what??

Provomon said:

I found an OEM carburetor on ebay and replaced the old one with the new carb.

Click to expand...

I highly doubt it is a real deal Briggs carb. Maybe there are some new old stock carbs still out there? Does it say Briggs and Stratton on the side some place?

Provomon said:

it will start to stall as soon as the air cleaner is put on the carb

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Put the choke on about half way. Install this phantom air cleaner and see if she runs.

That new carb will have to be gone through. Verify the fuel pickup tube is long enough, not cracked and has a good screen filter on the bottom.

Don't over torque the screws that hold the carb on. Use your weak hand with OPEN FINGERS to tighten the screws. Most people are right handed. Use your LEFT hand as it is physically weaker to purposely lower the screw torque value.

Make sure the carb to tank gaskets are on proper.

Could be a bad carb.

I've had to go though several making sure the fuel pump is working proper and the pickup tube was good. On a Chinese clone carb the pump wouldn't plunge into the body proper without some grinding on the carb body. New doesn't mean new.

Tons of pulsa prime videos out there.

slomo said:

Gas caps on pulsa prime carbs are normally wide open. Have large holes in the cap.

What do YOU think the engine is telling you?? It wants more what??

I highly doubt it is a real deal Briggs carb. Maybe there are some new old stock carbs still out there? Does it say Briggs and Stratton on the side some place?

Put the choke on about half way. Install this phantom air cleaner and see if she runs.

That new carb will have to be gone through. Verify the fuel pickup tube is long enough, not cracked and has a good screen filter on the bottom.

Don't over torque the screws that hold the carb on. Use your weak hand with OPEN FINGERS to tighten the screws. Most people are right handed. Use your LEFT hand as it is physically weaker to purposely lower the screw torque value.

Make sure the carb to tank gaskets are on proper.

Could be a bad carb.

I've had to go though several making sure the fuel pump is working proper and the pickup tube was good. On a Chinese clone carb the pump wouldn't plunge into the body proper without some grinding on the carb body. New doesn't mean new.

Tons of pulsa prime videos out there.

Click to expand...

Thanks everyone for your responses. You all were very helpful. I checked everything that was mentioned and replaced the filter element with an OEM filter from Amazon. Mounted the air filter, primed with a little ether, pulled the cord and it started right away. Runs like a new one. I can not identify one thing that solved the problem but thanks again for all your help. Next project for this 1986 Snapper mower is to tear it apart this winter, replace worn parts (if available), and repaint it. This mower is part of my family as I have had it since the late 1980s (bought it used at an auction) and to part with it would not have been good. Thanks again for your help.

Hello P.,

Glad you got it running.

One of the forgotten rules on those early pulse-jet carburetors is they were moody about starting if the fuel is below 1/2 tank.

The B&S push mowers carbs with the single tube were the worst for this problem.

When I first started out in a small engine shop back in the late 70's, it never failed that customers would bring mowers in with practically no fuel in the tank. Some of them would even get mad when we would fill the tank and the mower fired right up.

When you begin the Snapper project let us know if you need help. Make sure you provide the chassis information sticker numbers and also the engine information stamped into the starter cover. They produced millions of Snapper mower through the years and lots of new and used parts are still around for decent prices. I have a 1987 "model 6" rider with an 8HP B&S engine and a 30-inch deck.

I search Parts Tree and eBay to find most of my parts for that mower.

Jim's Fix It shop has a lot of Snapper rider repair and service videos.