Briggs and Stratton 19.5 HP Engine Issues

[GlockSpock]

19.5 HP Briggs and Stratton Twin Turbo Craftsman Mower

So, first I will attempt to give a bit of a backstory. In 2017, the last time I mowed I lost steering on my riding lawn mower. As such, I pushed the whole thing into the shed and let it sit over the winter. A few weeks ago, I fixed the steering issue. It works great now! However, at the time, I cranked it up and it would only run on full choke. Anytime I closed the choke it would die, 100% of the time. My research showed that was because it wasn't getting enough fuel.

So, over the last week, I rebuilt the carburetor. I used this kit from Amazon.com. As painful as it was to watch, this following video showed me what I needed to perform the rebuild:

This guy knows what he's doing, I just wish they would quit trying to be actors and just show me what I need!

So, Saturday, I completed that job and also changed oil. Cranked it right up and it ran better than it has ever ran for me before. I mowed ~80% of my yard for about 20 minutes. Then it started having issues again. Since then, I cannot get it to run full throttle. Even on full throttle, it sorta rumbles around and never runs high enough RPM to do anything. The choke is "in" or "off" when running, which is better than a week ago!

At this point, I "messed with" the fuel/air mixture a bit by screwing/unscrewing the single adjustment screw on the carburetor. I haven't had much luck with it. I think I can get it back to close where it needs to be by screwing it ~80-90% in.

What I've checked so far:

• Spark Plugs have fire (I haven't removed them yet, planning on checking that tonight to look at the gap)
• Carburetor seems to be getting fuel and enough of it (opening the plug at the carburetor drains gas out of it)
• Fuel filter seems to have good flow (disconnecting fuel line above filter and it flows freely out of from the tank through the filter)
• Gas Cap (supposedly an improperly sealed gas cap can cause issue, I've tried it with gas cap off as well)
• Air filter (it is dirty but I've tried running it with it off. Perhaps a bit better but unsure this is the problem)
• Battery (I've made sure the cables are nice and secure)
• Gas (Admittedly, I had a complete brain fart and put ethanol gas in in after fixing the steering. After fixing the carburetor, I suppose this ethanol gas was what I ran for 20 minutes. When I started having these issues, I drained at least half the gas out and replaced with 100% gas. There is probably still a certain percentage ethanol in the tank currently)

Here are my plans for tonight:

• Pull each spark plug and inspect gap and spark
• Possibly replace fuel/air filters
• Attach booster cables to see how it runs with juice from my car. I don't think it would be a battery issue but it will be quick to try in diagnosing. It cranks from the battery and shows charging "+" on the dash when running.

I have learned a lot throughout this, but generally feel pretty dumb right now and don't know exactly how to proceed. I don't want to break the carburetor open again but will if I have to, at least I know how this time. I'm wondering if running optimally for a few minutes may have broken something loose in the fuel line or carburetor and clogged something in the carburetor. I did try my best to get it clean but I'm open to the possibility I didn't do a good enough job. Also, ethanol seems to be the worst. I usually put 100% gas in it but since that was the first time of the season I completely forgot. If need be, tonight I can siphon all the gas out of it and try 100%.

Also, when I was rebuilding the carburetor, a small strip of paper in the kit instructed that I soak one of the pieces in oil. I didn't do this as I couldn't determine which part it was (it gave a part number). Now I'm wondering if the carburetor worked for a while but since I didn't oil something that caused something to become brittle, etc.

I'm looking for things to try. Maybe there is something that I'm not thinking of.

EDIT: To anyone that watches the above video, I have the three screw fuel pump version.

Edited May 7, 2018 by CZ9MM

[Omega]

Bad fuel was one of the money makers when I worked at JD, many don't drain their carbs (run it out of gas) so the fuel gums up and kills the carb.  Using an additive such as stabil is highly recommended as well, unless you can buy non-alcohol gas somewhere, and even then not a bad idea.  But always run it out of gas before you put it up at the end of the season.  Check your fuel lines as well, make sure there is no breaks in it, air enters and chokes the fuel/air mixture.  I take it you replaced or cleaned the float valve to make sure it operated smoothly?

[GlockSpock]

4 minutes ago, Omega said:

Bad fuel was one of the money makers when I worked at JD, many don't drain their carbs (run it out of gas) so the fuel gums up and kills the carb.  Using an additive such as stabil is highly recommended as well, unless you can buy non-alcohol gas somewhere, and even then not a bad idea.  But always run it out of gas before you put it up at the end of the season.  Check your fuel lines as well, make sure there is no breaks in it, air enters and chokes the fuel/air mixture.  I take it you replaced or cleaned the float valve to make sure it operated smoothly?

Didn't replace the float, but replaced the needle and cleaned all operational parts in the carb as much as I could (but still not confident it was 100%). I had planned on running it dry at the end of the season, but when the steering broke I forgot all plans to do so. My mistake. If tonight I cannot magically make it work by checking something simple (plugs, battery, etc), then I suppose it may be time to break the carb down again and give it a take two.

[peejman]

I also suspect gunk in the carb or a vacuum leak.  Does it have a vacuum operated diaphragm and slide?

[GlockSpock]

5 minutes ago, peejman said:

I also suspect gunk in the carb or a vacuum leak.  Does it have a vacuum operated diaphragm and slide?

I have slightly checked for vacuum leaks, I'll spend some more time with that tonight with a flashlight. As for the vacuum operated diaphragm, I think so. The fuel pump is attached to the carburetor and operates off a vacuum. Unsure exactly what you mean by "slide".

I'll check the hoses (air and fuel) that I can. Think I should try anything regarding the carburetor without dissembling it?

[GlockSpock]

Interesting note, I just watched more of the video I posted above. At 12:14, he mentions that the screw that I considered a mixture setting is a fixed jet and not an adjustment. Perhaps I need to keep it screwed in all the way.

[Sidecarist]

Drain the fuel tank and re fill with 50/50 seafoam and 100% gas. Run it for 10-15 min then let it sit overnight to let tgge seafoam work. Fill it with 100% gas and go. I've recovered several mowers & generators this way.

[GlockSpock]

5 minutes ago, Sidecarist said:

Drain the fuel tank and re fill with 50/50 seafoam and 100% gas. Run it for 10-15 min then let it sit overnight to let tgge seafoam work. Fill it with 100% gas and go. I've recovered several mowers & generators this way.

You mean 50% seafoam and 50% gas (100% gas), correct?

So, ~16 oz seafoam and 16 oz gas.

Edited May 7, 2018 by CZ9MM

[Erik88]

All I know is that without Youtube all hope for me would be lost. There is no telling how much money that website has saved me. 

Good luck CZ!

[GlockSpock]

I think a potential issue is that I was "adjusting" the main jet, I'm going to go home and screw that all the way in. According to the above video, that should be screwed all the way in.

Secondly, I guess I never messed with the actual idle adjustment at all as seen at 17:43. I'm going to go home, try screwing the jet in all the way as needed, and then turn that adjustment 1 full turn, slowly, counter clockwise. If that doesn't do anything, then I will reverse it back to the starting position.

[Chucktshoes]

By 100% gas I believe he means pure gas with no ethanol blend. 

[GlockSpock]

4 minutes ago, Chucktshoes said:

By 100% gas I believe he means pure gas with no ethanol blend. 

Right, so thus a 50% seafoam and 50% gas (that is 100%, no ethanol) mix. Right?

[Chucktshoes]

Yep. Ethanol is bad for all engines and especially murder on small engines. 

[GlockSpock]

8 minutes ago, Chucktshoes said:

Yep. Ethanol is bad for all engines and especially murder on small engines. 

I know. I usually respect that, greatly. Yet when I fixed steering the other day, I was eager to get everything running and I went to the nearest gas station without even giving a second thought about ethanol because I didn't remember to. I don't think that caused any issue (letting gas sit there over winter likely did thought).

I'm optimistic about getting this going tonight.

[peejman]

3 hours ago, CZ9MM said:

I have slightly checked for vacuum leaks, I'll spend some more time with that tonight with a flashlight. As for the vacuum operated diaphragm, I think so. The fuel pump is attached to the carburetor and operates off a vacuum. Unsure exactly what you mean by "slide".

I'll check the hoses (air and fuel) that I can. Think I should try anything regarding the carburetor without dissembling it?

You won't find vacuum leaks with a flashlight, you find them with aerosol carb/brake cleaner. 

Start the (cold) engine and squirt little blasts of carb cleaner at the various joints between the carb and the engine. Wait a few seconds after each squirt. If the idle surges, you have a vacuum leak. 

If it has a vacuum diaphragm, it has a slide too. The slide is behind the throttle butterfly and moves up/down based on engine vacuum to allow the appropriate amount of air to enter the engine. It keeps the engine from stalling with sudden throttle position changes. 

And yes, you need to snug up the main jet. Not too tight as you can break the tube it screws into. 

The standard starting point for mixture adjustment screws (aka air screw, pilot screw,... ) is 2.5 turns out from bottom. Screw it all the way in until it GENTLY bottoms out. Then back it out 2.5 complete revolutions. Tune from there.  This is mixture adjustment, not idle speed adjustment, which is generally a screw that adjusts the closed position of the throttle butterfly. 

[QuackerSmacker]

5 hours ago, peejman said:

I also suspect gunk in the carb or a vacuum leak.  Does it have a vacuum operated diaphragm and slide?

This would be my first guess

[GlockSpock]

Well, I have some more information. The first thing I did when messing with it this evening, I tightened that brass main jet up. Then I started looking at one that the video shows at 17:43. I messed with it a bit, attempting to see how it worked. In doing so, it started running much, much better. However, more importantly, I discovered that I had failed to attach a link the other day, as shown here:

I reattached that, optimistic that this was the problem and would fix everything. It took my about 30 minutes, and I came very close, but I just couldn't get it. I eventually adjusted that screw shown at 17:43 in quarter turn adjustments. It would idle very, very good. I could throttle up most of the way. However, most every time, at full throttle it would die. Engaging the blades would kill it. It would drive though decently. At some point, I hit rock bottom, this is the current state of the engine:

https://www.dropbox.com/s/0me7w16bj4znzth/Video May 07%2C 3 54 09 PM.mov?dl=0

(That link should take you to a Dropbox video showing the noise it is making).

So, unless that linkage came loose the other day, I literally have zero idea how I mowed at all with it disconnected.

Also, more relevant information:

Craftsman Mower: 917.270810

B&S Engine: 42E707

I never called myself a mechanic, I'm just brave enough to give things a try. Generally, with enough reading/Youtube, I can figure most things out. This is stumping me. I wish I hadn't messed with that one screw today, I wish I had noticed the 17:43 screw first.

Ok, so help me help you all out.

In the original video:

12:14: Main jet, not adjustable?

17:43: What do you call that?

Peejman, you were mentioning mixture adjustment screws, do I have them?

[GlockSpock]

11 hours ago, Omega said:

Bad fuel was one of the money makers when I worked at JD, many don't drain their carbs (run it out of gas) so the fuel gums up and kills the carb.  Using an additive such as stabil is highly recommended as well, unless you can buy non-alcohol gas somewhere, and even then not a bad idea.  But always run it out of gas before you put it up at the end of the season.  Check your fuel lines as well, make sure there is no breaks in it, air enters and chokes the fuel/air mixture.  I take it you replaced or cleaned the float valve to make sure it operated smoothly?

 

9 hours ago, peejman said:

I also suspect gunk in the carb or a vacuum leak.  Does it have a vacuum operated diaphragm and slide?

 

9 hours ago, Sidecarist said:

Drain the fuel tank and re fill with 50/50 seafoam and 100% gas. Run it for 10-15 min then let it sit overnight to let tgge seafoam work. Fill it with 100% gas and go. I've recovered several mowers & generators this way.

Quoted only to bring attention to my above post.

[peejman]

At about 5:30 is where he's showing the adjustable vs non-adjustable carbs. Both high speed and low speed adjustments. These adjustment are for the air/fuel mixture. 

6:40 is where he's talking about the main jet. It's not adjustable and needs to be screwed all the way in. Make sure it's clean by spraying with aerosol carb cleaner and compressed air  

12:14 isn't the main jet, that's the idle jet aka low speed aka slow jet. It controls the low rpm mixture. It's what he's adjusting at 17:43. A starting point is 2.5 turns out.  Again, this is air/fuel mixture, not idle speed, which is what he tweaks at 19:35.   

The last thing he's adjusting is the governor, which controls the maximum engine speed.  The dying at full throttle or when the blades are engaged tells me the governor isn't correct.  

The noise in your video sounds like the starter isn't engaging.  Could be a bad solenoid.  

 

 

[GlockSpock]

2 minutes ago, peejman said:

At about 5:30 is where he's showing the adjustable vs non-adjustable carbs. Both high speed and low speed adjustments. These adjustment are for the air/fuel mixture. 

6:40 is where he's talking about the main jet. It's not adjustable and needs to be screwed all the way in. Make sure it's clean by spraying with aerosol carb cleaner and compressed air  

12:14 isn't the main jet, that's the idle jet aka low speed aka slow jet. It controls the low rpm mixture. It's what he's adjusting at 17:43. A starting point is 2.5 turns out.  Again, this is air/fuel mixture, not idle speed, which is what he tweaks at 19:35.   

The last thing he's adjusting is the governor, which controls the maximum engine speed.  The dying at full throttle or when the blades are engaged tells me the governor isn't correct.  

The noise in your video sounds like the starter isn't engaging.  Could be a bad solenoid.  

 

 

Hmmm...thanks! I'm going through right now to the points you mentioned. For the governor, what timestamp are you talking about?

[peejman]

4 minutes ago, CZ9MM said:

Hmmm...thanks! I'm going through right now to the points you mentioned. For the governor, what timestamp are you talking about?

21:43. 

Getting it adjusted is an iterative process. Start with the idle and then get the high speed sorted. 

The carbs are really basic and don't respond well to sudden throttle changes. Bogging or stalling when just whacking it from idle to full throttle isn't unusual, especially if it isn't fully warmed up. 

[GlockSpock]

7 minutes ago, peejman said:

At about 5:30 is where he's showing the adjustable vs non-adjustable carbs. Both high speed and low speed adjustments. These adjustment are for the air/fuel mixture. 

6:40 is where he's talking about the main jet. It's not adjustable and needs to be screwed all the way in. Make sure it's clean by spraying with aerosol carb cleaner and compressed air  

12:14 isn't the main jet, that's the idle jet aka low speed aka slow jet. It controls the low rpm mixture. It's what he's adjusting at 17:43. A starting point is 2.5 turns out.  Again, this is air/fuel mixture, not idle speed, which is what he tweaks at 19:35.   

The last thing he's adjusting is the governor, which controls the maximum engine speed.  The dying at full throttle or when the blades are engaged tells me the governor isn't correct.  

The noise in your video sounds like the starter isn't engaging.  Could be a bad solenoid.  

 

 

So, at 12:14 he claims that is not an adjustment ("this is the one with the fixed jet"). Should this be screwed in all the way or 2.5 turns out like you suggest?

Ok, so the idle speed is what I was messing with last night.

I think I'm close.

[GlockSpock]

1 minute ago, peejman said:

21:43. 

Getting it adjusted is an iterative process. Start with the idle and then get the high speed sorted. 

The carbs are really basic and don't respond well to sudden throttle changes. Bogging or stalling when just whacking it from idle to full throttle isn't unusual, especially if it isn't fully warmed up. 

I have not messed with the governor. I think I'm close, if I can get the starter going again I think I can get everything.

So, first I should probably screw that idle jet out 2-3 turns. Then, I can adjust the idle speed. In taking another look at that video, I suspect I found another problem that I'm ashamed to admit.

At 6:30, where it shows the housing for the air filter that bolts to the carburetor, I think I made a mistake putting it back. He mentions three screws, let's just say I put four screws in:(

I now suspect that the "X" above is a vent allowing air into or out of the carburetor, etc. There is currently a screw in that. So, I'm going to go home, remove that screw, hope I didn't damage anything by making this mistake, set the idle jet out 2.5 turns, investigate the starter, and then take a look at the idle speed.

The governor should be good, I mowed all last season. I don't want to mess with it if I don't have to.

I hope my screwing a screw into that "X" didn't put any metal shavings into the carburetor.

[peejman]

46 minutes ago, CZ9MM said:

So, at 12:14 he claims that is not an adjustment ("this is the one with the fixed jet"). Should this be screwed in all the way or 2.5 turns out like you suggest?

Ok, so the idle speed is what I was messing with last night.

I think I'm close.

Depends on which version you have, adjustable or not. The adjustable version has a spring and a washer under the screw head. It should be set 2.5 turns out to start with.  The carb on the engine he's working with has this adjustment (17:43).  

He only shows the non-adjustable version briefly around 5:30. It appears to thread flush with the carb body. I'd presume it should be tightened snug. 

And yes, that extra screw probably isn't helping.  

Edited May 8, 2018 by peejman

[GlockSpock]

7 minutes ago, peejman said:

Depends on which version you have, adjustable or not. The adjustable version has a spring and a washer under the screw head. It should be set 2.5 turns out to start with.  The carb on the engine he's working with has this adjustment (17:43).  

He only shows the non-adjustable version briefly around 5:30. It appears to thread flush with the carb body. I'd presume it should be tightened snug. 

And yes, that extra screw probably isn't helping.  

I am 99% sure I have what he’s referring to as the non adjustable idle jet. I’ll go home, remove it, and upload a picture. 

I’m learning a lot. Too bad the learning process is typically a mistake, trial, and error process. 

Gonna kick myself hard if one of the main problems since the rebuild has been that extra screw.