The EPA loves me, Guess why.

[Ibanez616]

Got a free 4hp flatty from a friend of mine. After fixing all the tweakery (new word I just came up with :laugh: ) I fired it up, and man, this sucker could pass for a fog machine. I know its the rings or bore because it had a good amount of gas in the oil when I first drained it. I know its a long shot, but is there anything I can do to fix it without spending more than a few bucks? If not, I guess I'll just part it out? :shrug:

 

[jeff4298]

I'm not sure if they're still available but years ago you could by oversize rings. I bought a set for my 4 hp briggs and all I did was hone the cylinder and put the new rings on the old piston. It worked great and it lasted until I sold the mini-bike 3 years later. If my memory serves me they were like .005 oversize. I went to the dealer to price a new long block and they told me about the oversize rings. If you don't have a cylinder hone Sears sells one for like 30.00. Hope this helps.

 

[mr.modified]

Just put some 20w-50 in that baby. That would be cheapest.

 

[Bill Ellerby]

For oversize rings for your motor use the following p/n: 297576(+ .010); 297577(+ .020); and 297578(+ .030). Take the piston and rod out of the block and examine the cylinder real good. Take off the first ring from the piston without breaking it and set it inside the cylinder. measure the gap on the ring, more then .030 go with the .030 oversize rings. If you need to freshing up the cylinder you can get a honer at Auto Zone or HF and use a fine to extra fine stone ONLY. Good Luck

 

[oldfatguy]

It might be worth the time to pull the piston out of it to see if there is something going on that's an easy fix. I have seen rings rusted and stuck in the ring groove, even broken rings. The piston could have a crack in it . All of these would be easy to fix but if the rings are really that badly worn that it smokes like that then the rest of the engine like the crank etc. are probably shot too.

 

[Ibanez616]

Nope, I had it apart before firing it up and everything looked great. Bore was good, rings looked good, no problems with the piston. Crank was good too. :shrug:

 

[Bill Ellerby]

Problem being rings can look good but still be worn beyond specs. You really need to remove one and insert into cylinder to check just how much its worn. Had a briggs that ran great and put out white smoke. Pulled piston and removed the ring and found it worn .045 over the limit. Put standard set in and the compression is through the roof. How is your compression?

 

[oldfatguy]

Nope, I had it apart before firing it up and everything looked great. Bore was good, rings looked good, no problems with the piston. Crank was good too. :shrug:

did you check the breather to see if it's clogged ? Just take the oil cap off and put your thumb over it as you pull the engine over, if you feel a lot of suction in the crankcase the breather could be clogged . Try a compression test to see what it is that put a little oil on top of the piston to seal it and check it again. If it comes up a lot the rings are leaking. Also with the head off check if the piston is loose in the bore. Just bring it up to the top and use your fingers to see if the piston will move side to side [front to back] in the bore. On a badly worn engine the piston will be loose and rock back and forth in the cylinder. This is because the cylinder will wear oval or egg shaped at the top . These engine usually don't smoke like that unless they are really badly worn out or something broken or wrong with it.

 

[Richard Trotter]

Too much oil in the crankcase can cause smoking, or if the motor has been on it's side or up-side down would have same results.

 

[Ibanez616]

It's not the breather, I took off the tube and it still smoked. The piston Dosent rock in the bore, and it definitely dosent have too much oil, and hasn't been on its side.

 

[metal man]

It's not the breather, I took off the tube and it still smoked. The piston Dosent rock in the bore, and it definitely dosent have too much oil, and hasn't been on its side.

well going off what you have said . in going to guess the rings have bit the dust .you may be able to get away with just putting stock size back on and giving it a light hone out .
i got one like that the rings are gone bad like no compression but piston is good and tight in the bore . no ring ridge nothing just bad rings .
looking in the pdf book i have it looks like the rings should have a end gap of .010 and .020 on the hs40 so comp rings .010 and oil .020 :shrug:
do you have a book on this motor ? if you need one pm me your email address and ill send you a copy of the one i have .

 

[oldfatguy]

did you take the rings off the piston when you had it apart ? because the rings are different and there is a top that must face up when installed. Is it possible that one of the rings broke when you put the piston back in ? on the breather make sure the passage in the block is clear. Another thing to look for is if the rings are bad you will have oil and smoke coming from the breather too. Doing the compression test will help you find out if the rings are leaking, even if you don't have a compression tester you can still see if you feel a difference in the compression with the pull start after you put oil on the top on the piston to seal it . There are several things that can cause the smoking problem as you eliminate each one you will find the one causing your problem. Another thing could be that the engine just needs to run a while to break in after being apart. I had this with a 3hp Tecumseh that I pieced together from parts, when I first started it it blew out white smoke until it ran for about an hour then it stopped and ran fine. let us know how it turns out getting it to stop smoking. From what you said about the crank, piston and bore still being in good shape it will be worth putting a new set of rings in it.

 

[Jeff Clark]

You got me on this one with the title I was expecting a pic of a new Prius in the garage..

 

[Ibanez616]

well going off what you have said . in going to guess the rings have bit the dust .you may be able to get away with just putting stock size back on and giving it a light hone out .
i got one like that the rings are gone bad like no compression but piston is good and tight in the bore . no ring ridge nothing just bad rings .
looking in the pdf book i have it looks like the rings should have a end gap of .010 and .020 on the hs40 so comp rings .010 and oil .020 :shrug:
do you have a book on this motor ? if you need one pm me your email address and ill send you a copy of the one i have .

I actually have a hardcopy of the briggs manual, It should have some info on this engine, If not, I'll take you up on that offer. :thumbsup:

did you take the rings off the piston when you had it apart ? because the rings are different and there is a top that must face up when installed. Is it possible that one of the rings broke when you put the piston back in ? on the breather make sure the passage in the block is clear. Another thing to look for is if the rings are bad you will have oil and smoke coming from the breather too. Doing the compression test will help you find out if the rings are leaking, even if you don't have a compression tester you can still see if you feel a difference in the compression with the pull start after you put oil on the top on the piston to seal it . There are several things that can cause the smoking problem as you eliminate each one you will find the one causing your problem. Another thing could be that the engine just needs to run a while to break in after being apart. I had this with a 3hp Tecumseh that I pieced together from parts, when I first started it it blew out white smoke until it ran for about an hour then it stopped and ran fine. let us know how it turns out getting it to stop smoking. From what you said about the crank, piston and bore still being in good shape it will be worth putting a new set of rings in it.

Nope, I didnt take the rings off, I seriously doubt they broke because I took the head off and there isnt any gouging in the bore.

You got me on this one with the title I was expecting a pic of a new Prius in the garage..

Bahaha, Nope, Although I did just bring home a 85 Mustang with a 302. :laugh:

 

[metal man]

I actually have a hardcopy of the briggs manual, It should have some info on this engine, If not, I'll take you up on that offer. :thumbsup:

man im out of it big time . just realized your working on a briggs :doah::doah:
for some reason i was thinking it was a tec

 

[Richard Trotter]

Could it be sucking oil past the valve guides?

 

[jholland5760]

I agree with the old fat guy, I have seen many engines that have sit around for years fire and run but smoke like crazy. After a tear down, IF THE CYL WALLS ARE NOT WORN EXCESSIVELY, pull the piston and find the rings broken or rusted in the groove. Remove them, replace the rings and very carefully clean CLEAR TO THE BOTTOM OF THE RING GROOVE! hone lightly and replace. Start and smell the exhaust

 

[Ibanez616]

Rings looks fine. Not rusted, broken or stuck. They look normal.

 

[125ccCrazy]

if it's worth keeping then it's worth doing right...completely rebuild it..problem fixed :thumbsup:

 

[Ibanez616]

I dont have time or money right now, I have to do head gaskets on my Mustang. :hammer: