Hard starting Briggs & Stratton 3.0 hp lawnmower engine

Have a B&S on a 70's era Snapper 21" pusher with an aluminum deck. I believe the engine is probably 10 years newer than the rest of the mower.

Maybe 10 years ago I took it to a repair shop who installed a solid state unit to replace the points. Even with the solid state ignition it was never one-pull start, but as I recall it usually started with probably 3 - 5 pulls. Now it takes probably 20 pulls or more and monkeying with the throttle. Once it fires it runs like a clock, runs up and down the speed range fine. It's also easier to re-start once it's been running - though still not one pull. Doesn't seem to use an inordinate amount of oil, no discernible smoke out the exhaust. It gets what I'd call moderate use. I'm in central Florida so it gets run bi-weekly or so during the rainy months, not at all during the months of what passes for a winter down here.

I'm mechanically inclined but not well-versed on the theory of this kind of engine. I've had it broken down far enough to remove and flush the gas tank, change the points when it had points, replace the pull rope. I've change the spark plug of course. I know it should start much easier than it does. Any suggestions where to look, what to tweak? There isn't that much to it from what I can see, so it shouldn't be that difficult. I believe this mower has a lot of life left in it.

Thanks for all input.

Reply to
muzician21
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Look, I didnt study this as well as I should have. BS engines with solid state ignition normally start pretty well.

I suspect you might be having fuel delivery problems. I have rebuilt the "carburetors" on some BS implements we have here several times.

In these cases, I have to take the fuel tank off, wash it well with water, and then carefully dry it. Then, I remove the carburetor, clean it, and put it back together with a new diaphragm. This is important. Just a carburetor job is not enough.

Ignition may have to be followed up as well.

Let us know how you are proceeding. I have had only one BS engine really disappoint me, and that was because the casting was make of parmesan cheese.

Reply to
HLS

try a quirt of starting fluid in the carb. Will it start any faster? I too think it's a fuel delivery issue if it'll start quicker on the starting fluid.

Does it have a choke setting?

You can also see if the solid state unit is adjustable. Maybe the gap is too far apart.

Reply to
m6onz5a

Not familiar with this particular engine, but it sounds like a gas delivery/mixture problem. Choking can be real critical with these. This is the first year I've had no problem starting my 2-cycle weedwacker because I've learned the primer bulb needs to be pumped up hard, the exact choke setting it likes, and that it has to be unchoked immediately upon firing. Only took me 5 years, but I've got it starting in 3 pulls. I'd start by maybe looking in the carb for wetness, and trying 3 to 5 pulls at different choke settings. But you have to let it dry out between tries so you're not confusing the issue. Once you know what works, you're all set. Until it doesn't work any more. That's what I like about the Honda I have on my Craftsman.

3 horse I think, 4-cycle. It starts first pull after sitting all winter. Every time for about 6 years now. Original plug. And I never drain the gas or use a gas additive on anything. Not saying don't, just that I don't bother.

--Vic

Reply to
Vic Smith

If this is an older Briggs without a primer...they make an after--- market primer on a replacement gas cap. Stens.com should have it (they used to). It makes starting a snap.

Reply to
pheeh.zero

Sounds like it's time to do a little work on the carburetor. Put a new diaphragm in it if it the older type that uses those. As the motors age it's worth while to make a priming port in the air cleaner, drill a hole you can plug after starting and spray some carb cleaner in it to start it. Also check the valve clearances (those easy spin engine valve clearances are pretty critical for easy starting) and a good spark plug. Would help if you posted the engine model number. On newer ones with primer bulbs and bowl/float it's common for the main jet to get clogged over winter.

Reply to
Fat Moe

My lawn mower has a Briggs & Stratton engine with a primer bulb on it.It usually starts on the second pull.

Yesterday, at the Lowe's store, I saw some 4 stroke engine weed trimmers.I am thinking I might buy one of those.I wonder if I could rig it up on a junk lawn more frame with a windshield wiper motor? I could cut my lawn mowing time way down, if it would work. cuhulin

Reply to
cuhulin

Sure, and add a prop to it for hanging it on the boat. Not quite sure what the wiper motor is for, but go for it.

--Vic

Reply to
Vic Smith

If you hold a broom stick (horizontally) near the end with one hand and push/pull the end of the broom stick back and forth in an arc, you will see what I am talking about.I would need to make a place for the battery to run the windshield wiper motor.There is a guy in Florida, he uses something similar to use his metal detectors on the beaches. cuhulin

Reply to
cuhulin

[snip]

I had a mower given to me recently by a co-worker. It uses a B&S engine. I had to take the carb apart and clean out the main jet because he hadn't used it in years. The mower would not stay running unless I did that however, it *would* start up still on the first or second try if primed properly. It would also continue running if a 2nd person was available to continue priming it. I don't know anything about mowers but if the OP's mower takes that long to start could it still be an issue of a dirty/clogged carb? I'm just comparing what you said to what I recently experienced.

Reply to
Brandon McCombs

Does it have one of those push ball primer gizmos? I've got a BS with one, it's about 5 years old now. Supposedly it takes 3 to 4 pushes of the ball to prime it. But that has never worked. It takes 13 pushes, and has since it was new, to get it primed. then it starts on the first pull and runs just fine.

Reply to
Ashton Crusher

I push the primer bulb thingy on my lawn mower engine three or four times.That might be too much priming because usually on the first pull on the starter rope the piston locks up and my lawn mower almost lifts up off of the ground.The second pull almost always starts the engine running.

I used to have a lawn more that was about fourteen years old.About seven or eight years ago, some people moved into a house next door to me.That guy over there would borrow my lawn mower to mow that yard.The third time he borrowed my lawn mower, he loaned it to his sister who lives in another part of town.I never saw my old lawn mower again, I had to go buy a new lawn mower.I really liked that old lawn mower too, because the right rear wheel was in front of the grass discharge chute and the handle was mounted in the middle of the frame.That lawn mower was easier for me to turn the corners and all I had to do was flip the handle from front to rear when I was mowing my yard.I wish they still made lawn mowers like that one. I never will ever loan my lawn mower to anybody ever again. cuhulin

Reply to
cuhulin

It certainly seems that there's a fuel problem when cold, since you say the engine runs fine once started.

A couple of suggestions, with apologies if they're not relevant due to the layout of your particular engine:-

1) Remove the air cleaner and see if you can look into the carburettor's air intake pipe. Normally there will be a spring-loaded butterfly valve, which is closed when the throttle is in the "start" position. If there's any obstruction preventing this butterfly valve plate from closing properly it can allow too much air to enter in the start position, so the start mixture isn't rich enough. 2) If the carburettor has a priming bulb (which you push to prime the engine), give it two or three pushes while you're looking into the intake pipe, and confirm that raw fuel is being squirted in there.

My mower starts first pull, but only since I realised that it takes a little time for the raw fuel squirted in by the primer bulb, to evaporate.

These days I normally give the bulb four pushes, take the cap off the gas tank, and then fill the tank from my fuel can. By the time I've done this and replaced the cap, the raw fuel has mostly evaporated, and the engine draws in vapour instead of liquid fuel, to start on the first pull.

Cheers, John S

(follow-up set to rec.autos.tech, where I saw your post)

Reply to
John S

muzician21 wrote: Now it takes probably 20 pulls or more and

The issue is that the engine needs a rich mixture to start when cold. There are several different ways that the engine (carb) could be designed to do that. In your case it probably has a choke. If it was the original 30 year old engine the choke would probably be part of the throttle control. The procedure for starting the engine would be to set the throttle to the start position and then when the engine started you would move the throttle control lever to the run position. On this design the throttle cable was mechanically linked to the choke plate. Sometime in the 80's they changed that to an automatic choke where a spring closed the choke plate and then a diaphragm used engine vacuum to pull the choke open once it started. On newer engines there is also the system that eliminates the choke completely and replaced it with a primer bulb where you pump a little gas (others have described the process).

So the first thing you need to do is identify which method it uses to deliver extra gas on cold starts and then figure out why it is not working as designed.

-jim

Reply to
jim

A motor that old may be worn out and not have enough compression to start easily or have good power. Have you tried starting fluid. Electonic ignition modules eventualy fail, hard starting was my first sign of mine failing. If you have ever hit anything and stalled the mower the flywheel key could be bent throwing off timing. At that age it could be many things.

Reply to
ransley

Part no.125-492

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Reply to
pheeh.zero

Altavoz lives on

Reply to
HLS

I have found that a lot of times the muffler is plugged. I have got some good byes because of a plugged muffler.

Reply to
JP

If the engine plant is in Milwaukee, they probably used cheddar.

Joe

Reply to
Joe

An old buddy of mine used to give me his lawn mowers whenever some little something went wrong with them.One of them had a cracked priming bulb on it.Those little aluminum block engines regardless of what they are used on are not designed and built to last a long time.Cast iron engines are much better. cuhulin

Reply to
cuhulin

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