Briggs and Stratton Lawn Mower Heartache

TurboT · 07-09-2010, 10:24 PM

Hi Guys,

I'm having some heartache with my lawn mower. It's a 4hp B&S motor with the carb mounted on top of the gas tank.

At the start of the season, I was having trouble keeping it running as the fuel primer bubble would suck itself up tight in it's hole and in my opinion, kill the gas flow. I thought this was perhaps from some bad fuel and that it would work itself out as it ran more for the season. It eventually died as I was then getting no fuel into the carb eventually, and no primer function from the ball at all.

I've replaced the carb gasket and rubber diaphram and now have fuel flowing again, but the primer ball is still sucking itself into oblivion and stopping it from running. (like too much vacuum)

I also have an overspeeding problem with it and replaced the governor spring as well, which has still not completely fixed the problem. I think this may just be some cabling tension and might be able to fix this if I could keep the bloody thing running long enough. (When it does slow down I still have the two much vacuum problem)

Any help here would be appreciated.

Weldangrind · 07-09-2010, 11:23 PM

Try running without the fuel cap to see if the vent is plugged.

katoranger · 07-10-2010, 12:08 AM

Yes, sounds like a plugged vent. I have one of those that I got at Goodwill 3 years ago for $14. Still mows the grass.

Also a tip. Tilt the engine toward the plug and it primes the carb when cold.

Allen

TurboT · 07-10-2010, 12:55 AM

Hey guys thanks for the input. I didn't mention I pulled off the gas cap and cleaned out the holes as I thought this might be the problem.

The only other thing I can think of is perhaps there is junk in the gas tank and it's plugging the dipper screen again, or the crank breather tube is plugged (how I don't know) .. I will have to look at it again tomorrow I ran out of patience today.

If anyone can think of anything else I'm all eyes.

Weldangrind · 07-10-2010, 01:01 AM

What I think is that you should come and grab my spare Honda while your mower is down.

BTW, I think that a plugged vent tube would create smoke. The plugged dip tube has potential.

TurboT · 07-10-2010, 01:05 AM

Quote:

Originally Posted by Weldangrind

What I think is that you should come and grab my spare Honda while your mower is down.

BTW, I think that a plugged vent tube would create smoke. The plugged dip tube has potential.

Thanks mate I can borrow my neighbours if I get stuck though. (already did that once)

With it being so hot now I don't think the grass will grow that much but you know it's one of those things that bothers me it's not running right.

katoranger · 07-10-2010, 01:15 PM

Hot. Been 90F plus for the past month here with 90% humidity. I get my stuff done in the morning.

Have you tried googling for an answer? Those briggs carbs can be a pain to get set right.

Allen

Reveeen · 07-10-2010, 02:31 PM

Here, I have found, that in the spring, I HAVE to remove the gas tank from the carb, and clean out the varnish out of the fuel pick-up. I spray carb cleaner in it, then blow it out with compressed air.

TurboT · 07-10-2010, 05:38 PM

Quote:

Originally Posted by Reveeen

Here, I have found, that in the spring, I HAVE to remove the gas tank from the carb, and clean out the varnish out of the fuel pick-up. I spray carb cleaner in it, then blow it out with compressed air.

Thanks mate. I've been there a couple times but perhaps I've done a less than a satisfactory job. I don't have any carb cleaner here (stuff just reeks) but I've been using some engine degreaser and tried some WD-40. I'm about to go attack this thing again to see if the screen on the pickup is plugged again, and I'm going to dump the gas and clean the tank out as well and hope I solve my problem.

TurboT · 07-10-2010, 09:05 PM

Hey gang,

Took the carb off again and saw this build up of crud on the bottom of my dipper/pickup. See the copper crud on the screen?

That's all from about 5 minutes of running.

Drained tank, cleaned, rinse and repeat a few times. All back together with fresh premium gas seems to have solved one problem. Still have a hard time keeping it from overspeeding but it just takes a bit of finesse.

Thanks for the input.

katoranger · 07-10-2010, 10:30 PM

You can adjust the governor spring by stretching it out. I think stretching makes it slow down.

SpudRider · 07-11-2010, 03:09 AM

I'm glad you got it fixed, Turbo!

Spud

TurboT · 07-11-2010, 05:34 AM

Quote:

Originally Posted by SpudRider

I'm glad you got it fixed, Turbo!

Spud

Me too. Now my wife can cut the grass. :P

Kato, I hadn't thought of stretching it. I've been messing with the throttle cable length and adjustor on the side of the engine cover. It seems okay till I bump something and it pushes on the case and makes it rev up. Think I might've stretched the thread too much today trying to tighten it so it wouldn't move.

The gov spring is new but I guess that doesn't mean anything.

katoranger · 07-11-2010, 03:11 PM

The spring is how you adjust the governor. Briggs can be complicated.

Allen

TurboT · 07-11-2010, 07:15 PM

Quote:

Originally Posted by katoranger

The spring is how you adjust the governor. Briggs can be complicated.

Allen

It hasn't seemed too bad, stretching the spring makes sense when you figure out how it's working to open and close the butterfly valve in the carb. I had a bugger of a time getting the clip back on the other day but once you get on to it it's not too bad.

I'll mess with it some more to get it working right.

07-09-2010, 10:24 PM	#1
TurboT Join Date: Sep 2008 Location: Surrey, B.C., Canada Posts: 2,185	Briggs and Stratton Lawn Mower Heartache Hi Guys, I'm having some heartache with my lawn mower. It's a 4hp B&S motor with the carb mounted on top of the gas tank. At the start of the season, I was having trouble keeping it running as the fuel primer bubble would suck itself up tight in it's hole and in my opinion, kill the gas flow. I thought this was perhaps from some bad fuel and that it would work itself out as it ran more for the season. It eventually died as I was then getting no fuel into the carb eventually, and no primer function from the ball at all. I've replaced the carb gasket and rubber diaphram and now have fuel flowing again, but the primer ball is still sucking itself into oblivion and stopping it from running. (like too much vacuum) I also have an overspeeding problem with it and replaced the governor spring as well, which has still not completely fixed the problem. I think this may just be some cabling tension and might be able to fix this if I could keep the bloody thing running long enough. (When it does slow down I still have the two much vacuum problem) Any help here would be appreciated. __________________ My Blogs: Chinese Motorcycle Blog A Man's Blog
	0

07-09-2010, 11:23 PM	#2
Weldangrind Join Date: Mar 2009 Location: Sardis, BC, Canada Posts: 25,977	Try running without the fuel cap to see if the vent is plugged. __________________ Weldangrind "I figure I'm well-prepared for coping with a bike that comes from the factory with unresolved issues and that rewards the self-reliant owner." - Buccaneer
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07-10-2010, 12:08 AM	#3
katoranger Join Date: May 2007 Location: Altamont, Kansas Posts: 15,103	Yes, sounds like a plugged vent. I have one of those that I got at Goodwill 3 years ago for $14. Still mows the grass. Also a tip. Tilt the engine toward the plug and it primes the carb when cold. Allen __________________ You meet the nicest people on a Honda Clone.
	0

07-10-2010, 01:01 AM	#5
Weldangrind Join Date: Mar 2009 Location: Sardis, BC, Canada Posts: 25,977	What I think is that you should come and grab my spare Honda while your mower is down. BTW, I think that a plugged vent tube would create smoke. The plugged dip tube has potential. __________________ Weldangrind "I figure I'm well-prepared for coping with a bike that comes from the factory with unresolved issues and that rewards the self-reliant owner." - Buccaneer
	0

07-10-2010, 01:15 PM	#7
katoranger Join Date: May 2007 Location: Altamont, Kansas Posts: 15,103	Hot. Been 90F plus for the past month here with 90% humidity. I get my stuff done in the morning. Have you tried googling for an answer? Those briggs carbs can be a pain to get set right. Allen __________________ You meet the nicest people on a Honda Clone.
	0

07-10-2010, 12:55 AM	#4
TurboT Join Date: Sep 2008 Location: Surrey, B.C., Canada Posts: 2,185	Hey guys thanks for the input. I didn't mention I pulled off the gas cap and cleaned out the holes as I thought this might be the problem. The only other thing I can think of is perhaps there is junk in the gas tank and it's plugging the dipper screen again, or the crank breather tube is plugged (how I don't know) .. I will have to look at it again tomorrow I ran out of patience today. If anyone can think of anything else I'm all eyes.
	0

07-10-2010, 02:31 PM	#8
Reveeen Join Date: Jun 2009 Location: orbital platform Posts: 741	Here, I have found, that in the spring, I HAVE to remove the gas tank from the carb, and clean out the varnish out of the fuel pick-up. I spray carb cleaner in it, then blow it out with compressed air.
	0

07-10-2010, 09:05 PM	#10
TurboT Join Date: Sep 2008 Location: Surrey, B.C., Canada Posts: 2,185	Hey gang, Took the carb off again and saw this build up of crud on the bottom of my dipper/pickup. See the copper crud on the screen? That's all from about 5 minutes of running. Drained tank, cleaned, rinse and repeat a few times. All back together with fresh premium gas seems to have solved one problem. Still have a hard time keeping it from overspeeding but it just takes a bit of finesse. Thanks for the input.
	0

07-10-2010, 10:30 PM	#11
katoranger Join Date: May 2007 Location: Altamont, Kansas Posts: 15,103	You can adjust the governor spring by stretching it out. I think stretching makes it slow down. __________________ You meet the nicest people on a Honda Clone.
	0

07-11-2010, 03:09 AM	#12
SpudRider Join Date: Jul 2008 Location: Idaho Posts: 25,054	I'm glad you got it fixed, Turbo! Spud __________________ Spud "Never argue with an idiot. He will drag you down to his level, and beat you with experience." Mark Twain 2015 Zongshen ZS250GY-3 (RX3) 2006 Zongshen ZS200GY-2 (Sierra 200) 2005 Honda XR650L 2004 Honda CRF250X 1998 Kawasaki KDX220 Mods made to my Zongshen ZS200GY-2: http://www.chinariders.net/showthread.php?t=6894
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07-11-2010, 03:11 PM	#14
katoranger Join Date: May 2007 Location: Altamont, Kansas Posts: 15,103	The spring is how you adjust the governor. Briggs can be complicated. Allen __________________ You meet the nicest people on a Honda Clone.
	0