Briggs 2.5 Motor Help?

[say2345]

Hello,

I have a Briggs 2.5 hp motor from a Sears bike (70's ish). It did run untile I tried to adjust the carb, because it wasn't putting out much power. I have worked my fingers to the bone trying to restart it and it just wont fire. Its come close, but no joy. It has fuel, its throwing a spark. I have tried to reset the carb to its orginal settings. Any one know what else I might try? also, in the event that I do get it restarted are there any easy fixes to get it running better, little adjustments ect. The Model numbers are:

61102 940536 5908310

as I have stated before, I am new to this, and a computer tech. not very good with engines. My kids are really ready for me to get this thing running again. Thanks for any help.

 

[Oldsalt]

There is a screen at the end of the tube, the little one that dips down into the gas tank, that can get pluged. If it's got good spark then it's probably a fuel problem, however it can be someting like a bad spark plug. Drop the tank, pull the carb and maks sure the diaphram in the side of the carb is still good and clean the screen [also there is usually a 'check ball' in that tube above the screen] useing carb or brake cleaner. Also change the plug.

 

[Tom S.]

I'm glad to hear from another Oregon minibiker. Old Salt knows lots more about engines than I do (look at his photos!), but I probably wouldn't take it apart just yet. The engine #s seem to indicate it was built in '59 (see below), and the embossed recoil housing also looks about that age. That's pretty old. Maybe the lack of power comes from a low compression (worn barrel or rings or valves), and no amount of messing with the carb will help. Can you feel it bump against the compression stroke when you pull the rope? What adjustments did you make to the carb? There isn't much you can do to them. Did you note the original settings? If you've put the carb back the way it was when the engine ran, it should still run unless you've changed something else. Is the sparkplug wet? If so, put in a clean, dry plug and try again. It has an oil bath air filter. Did you add too much oil? Maybe that would make it foul the plug. Is the plug dry? Then follow Old Salt's suggestion. That's about all I can offer w/o seeing it in person. I looked as closely as I could at your photos, and I doubt that your carb has a diaphragm, but not 100% sure. Not all B&S engines have a diaphragm carb. A close-up of the side of the carb closest to the exhaust pipe will help to determine the type of carb you have. Also, you can find lots of specs, diagrams and troubleshooting tips on line (all hail the Google search). Or you could buy a shop manual for about $20 (all hail eBay). If all else fails, you can frequently find lawn edgers w/newer B&S engines for well under 100 bucks on Craigs List. I saw 3 or 4 of them around Portland last weekend. Here's one now.

3 hp gas edger.

Go here, then scroll to the bottom of the page to learn a little more about your engine #s.

Identifying your engine

 

[INJUNTOM]

Got any pics of it?

 

[Tom S.]

Got any pics of it?

His photos are in the gallery.

 

[MINI-MATIC]

Hi,your carb is definately a vacujet,no diaphragm carb.With the age of the engine,you should check the valve lash.This is located under the small cover under the carb area ,this is where the valve springs are and where the valves meet the lifters.Useing feelers guages with the piston at the top of the compression stroke,there should be about .005/.007 clearance on the intake valve and about .007/.009 clearance on the exhaust valve.If these measurements are out of tolerance,then the valves need to be removed,relapped in,and then the correct lash needs to be accomplished by grinding the ends on the valves to the correct clearance's as mentioned above.Hopefully,this isn't the issue.Make sure also that the points are corrctly set and in good clean,dry condition,if there's any sign of oil in the points area,then either the crank seal is bad or the points plunger and or bore for it is worn.Also,check the flywheel key,that it isnt sheared or partially sheared,and try a new spark plug.Finally,put a new intake gasket on the carb if you already havent done so.I hope one of these above issues will solve your problem.

 

[Oldsalt]

I'm glad to hear from another Oregon minibiker. Old Salt knows lots more about engines than I do (look at his photos!), but I probably wouldn't take it apart just yet. The engine #s seem to indicate it was built in '59 (see below), and the embossed recoil housing also looks about that age. That's pretty old. Maybe the lack of power comes from a low compression (worn barrel or rings or valves), and no amount of messing with the carb will help. Can you feel it bump against the compression stroke when you pull the rope? What adjustments did you make to the carb? There isn't much you can do to them. Did you note the original settings? If you've put the carb back the way it was when the engine ran, it should still run unless you've changed something else. Is the sparkplug wet? If so, put in a clean, dry plug and try again. It has an oil bath air filter. Did you add too much oil? Maybe that would make it foul the plug. Is the plug dry? Then follow Old Salt's suggestion. That's about all I can offer w/o seeing it in person. I looked as closely as I could at your photos, and I doubt that your carb has a diaphragm, but not 100% sure. Not all B&S engines have a diaphragm carb. A close-up of the side of the carb closest to the exhaust pipe will help to determine the type of carb you have. Also, you can find lots of specs, diagrams and troubleshooting tips on line (all hail the Google search). Or you could buy a shop manual for about $20 (all hail eBay). If all else fails, you can frequently find lawn edgers w/newer B&S engines for well under 100 bucks on Craigs List. I saw 3 or 4 of them around Portland last weekend. Here's one now.

3 hp gas edger.

Go here, then scroll to the bottom of the page to learn a little more about your engine #s.

Identifying your engine

Tom

I know you know a lot more about these engines than I! All I can offer is what has sorta worked for me when I try to get a reluctant one to run. On one occation I changed the coil/points/condensor twice and changed the carburator and was about to change to another carb [on a 4 HP Briggs] when my eldest son came in and said to try a different plug. That's all that was wrong! On old Briggs engines that have been sitting for years I have found that the pick-up tube screen and or check valve are the most frequent offenders.

 

[Tom S.]

Tom

I know you know a lot more about these engines than I! All I can offer is what has sorta worked for me when I try to get a reluctant one to run. On one occation I changed the coil/points/condensor twice and changed the carburator and was about to change to another carb [on a 4 HP Briggs] when my eldest son came in and said to try a different plug. That's all that was wrong! On old Briggs engines that have been sitting for years I have found that the pick-up tube screen and or check valve are the most frequent offenders.

Thanks, but I've seen the photos of your race car and miniature engines and other toys. You clearly know your stuff. My strong points are breaking things and starting projects that don't get finished. :smile:
I think we agree that in this case the spark plug is the easiest place to start, and the place most likely to produce a good result and/or help ID other problems. But we need to hear from say2345 again!

 

[say2345]

Sorry its been a few days, I'd like to thank all of you for your advice and tips. Its been one of those weeks and I have not had a chance to work on the bike as of yet. My plan is to work on it tomorrow. I will let you all know how it gose. Thanks again for all your help, you guys are great!

Scott:smile:

 

[say2345]

I got it running! The fuel line/tube had come off the carb. I put it back in and it fired right up. Thanks to all who helped. I rode it out on the road, and had a great time! It dose about 20 mph or so. I am disabled and have a bad back, but it was still worth the pain. I cant wait to ride it again. Thanks :smile::thumbsup: