Surging engines - causes? remedies? tips or tricks

[Howie 886]

Those look like what I have. Believe most of those carbs are the same internally.

[Chestnut 315]

On 4/27/2021 at 6:32 PM, Jeff-C175 said:

 

I think I saw a YT video yesterday which said pretty much the exact same thing... was that your video?

Not my video. Glad you were able to get it sorted. Those precision drills sound like a handy thing to have, but a luxury for most of us.

 

 

 

[Jeff-C175 7,202]

3 hours ago, Chestnut said:

Those precision drills sound like a handy thing to have, but a luxury for most of us.

 

Yes, a luxury if it's not something that you actually use on a regular basis.  I haven't lately, but I used them extensively when making printed circuit boards for another hobby and had to drill numerous itty bitty holes.  In the set I've really only ever used three sizes.  I took to buying 12 packs of the single sizes I needed after a while.  I've got a LOT of dull ones and they are purt near impossible to sharpen due to their size.  Why don't I throw them out?  "Hello, my name is Jeff and I'm a hoarder"  

 

Who knows?  Maybe someday I'll build a model skyscraper out of them?  

Edited April 29, 2021 by Jeff-C175

[DennisThornton 4,769]

Tricks won't work all the time but when they do!  This has worked for me many a time though it has sometimes taken several times.

Breather off to be able to place my hand completely over the carb opening and seal it off with pressure.  Rev up the engine and suddenly and completely seal off all air flow to the carb, which creates quite the vacuum and very often pulls out the little bits hiding where they shouldn't be.  So easy to repeat I'll try several times before giving up.  It that doesn't work then it's some miracle in a can such as Sea-Foam and with those two I very seldom have to order a rebuild kit!

[Handy Don 12,232]

On 4/26/2021 at 12:51 PM, Chestnut said:

I've had and fixed the dirty carb surging issues on several small engines, but the Subaru Robin on my generator didn't change after several cleanings. It actually was the governor on this one.

My neighbor's Robin is surging. What did the governor need?

 

[Handy Don 12,232]

On 4/27/2021 at 8:37 PM, OutdoorEnvy said:

Glad you got it sorted out.  The aftermarket stuff is always hit or miss.  Put this one in the memory bank though...I know with some new honda engines they surge from day one.  There's a youtube channel called "Steve's small engine saloon" that has a good fix for it on his channel where he drills out the main jet a tad larger than factory.  That same issue seems to show up more lately on all kinds of stuff yours did.  Anyways...thanks for the update and again glad it worked out for you and your neighbor...

With the changes in regs with regard to small engine pollution, ALL the manufactures err on the lean side. If fuel injection was cheaper, they'd all be using it!

[Chestnut 315]

10 hours ago, Handy Don said:

My neighbor's Robin is surging. What did the governor need?

 

The screw on the left adjusts the length (tension) of the spring to the governor arm. There's a stop nut holding the screw in position. I just loosened the stop nut and made a small adjustment to the screw with the engine running. Good idea to mark the screw position before you start. I could hear it smooth out as I went. I can't remember whether I had the inductive tachometer when I did it, but I have one now and I'd use it if I had to do it again.

 

10 hours ago, Handy Don said:

 If fuel injection was cheaper, they'd all be using it!

It's coming. My mother in law had to replace her lawn tractor a few years ago. The Cub Cadet she bought has EFI.

[Handy Don 12,232]

4 hours ago, Chestnut said:

The screw on the left adjusts the length (tension) of the spring to the governor arm. There's a stop nut holding the screw in position. I just loosened the stop nut and made a small adjustment to the screw with the engine running. Good idea to mark the screw position before you start. I could hear it smooth out as I went. I can't remember whether I had the inductive tachometer when I did it, but I have one now and I'd use it if I had to do it again.

 

It's coming. My mother in law had to replace her lawn tractor a few years ago. The Cub Cadet she bought has EFI.

Thanks, now I can offer to help him out! On generators I just plug my VOM into the AC outlet and look for where it hits 60hz and the right voltage.

[Chestnut 315]

4 hours ago, Handy Don said:

On generators I just plug my VOM into the AC outlet and look for where it hits 60hz and the right voltage.

An even better idea. 

Today was oil change day and I thought I jinxed myself. When I started it to warm the oil it was running a bit fast. I moved the governor arm and it slowed down but started to surge. Smoothed out when it warmed up.

[Jeff-C175 7,202]

12 hours ago, Handy Don said:

it hits 60hz

 

With no load the freq should be a bit higher, 62 - 63 Hz.

[Handy Don 12,232]

7 hours ago, Jeff-C175 said:

 

With no load the freq should be a bit higher, 62 - 63 Hz.

You are right! I should have noted I do final adjustments under load. 

[Lee1977 6,659]

Jeff what year model is you 8 HP Briggs. I have a 8 Briggs on a 1989 Troybilt tiller runs good at half choke.

[Jeff-C175 7,202]

33 minutes ago, Lee1977 said:

what year model is you 8 HP Briggs

 

At least ten years old, can't recall exactly!

 

I'm hesitant to try and fix it since it starts first pull and runs fine at half choke.

[Lee1977 6,659]

I ask the local mower shop about it, he said it couldn't be fixed they have been in business for ever, I worked there for his father one summer back in1962 assembling mowers.

This is what I was assembling. The government got on the safety thing and put all the small builders out of business. The one in the picture is on it's filth engine, 1958 model.

[Jeff-C175 7,202]

15 minutes ago, Lee1977 said:

he said it couldn't be fixed

 

I understand their stance.  But ANYthing can be fixed.  They either don't want to, can't do it without charging too much or perhaps breaking some stupid law.  Or maybe they just don't know how to fix it and aren't willing to take the time to learn. (time is money, goes along with charging too much)

 

It's actually probably pretty simple but one has to be willing to get into the guts of the fuel delivery system and determine how to richen the mixture enough that the engine runs properly.

 

At the end of the day, if it runs fine on half choke, the solution is simple... run it at half choke!  

 

Patient: "Doc, it hurts when I move my arm like this!"

Doc: "Don't move your arm like that!"

[Jeff-C175 7,202]

27 minutes ago, Lee1977 said:

This is what I was assembling

 

OMG LEE!  You'll lose a finger on that thing just looking at it!  Where are the 10 pounds of safety covers and kill switches and 'dead man' switches, and, and, and...

 

Oh the horror!  I don't see ONE CAUTION LABEL!  

 

Ain't it sad that we've turned into a society of litigious sheeple without any common sense ?

 

That machine looks AWESOME!  I would own one in a heartbeat if I saw it for sale locally.  Looks like the deck housing is 1/4" cast aluminum!  Wow...

Edited May 5, 2021 by Jeff-C175

[kpinnc 12,056]

34 minutes ago, Jeff-C175 said:

 

Ain't it sad that we've turned into a society of litigious sheeple without any common sense ?

Paw Paw used to call folks that got hurt on stuff like that "natural selection in action".

 

...But then I came along and changed his mind!

[Jeff-C175 7,202]

9 hours ago, Lee1977 said:

assembling

 

Lee, what would get connected to this 'hitch' that one would not trip over?

 

[lynnmor 7,306]

32 minutes ago, Jeff-C175 said:

 

Lee, what would get connected to this 'hitch' that one would not trip over?

 

 

One of these of course:

 

[Jeff-C175 7,202]

10 minutes ago, lynnmor said:

One of these of course:

 

Wait... what the heck?  Is it Halloween already?

 

Or is that your OSHA mandated PPE ?

 

 

And there's no wheels on that mower!  Is that the "Flymo" version?

 

Edited May 5, 2021 by Jeff-C175

[lynnmor 7,306]

1 minute ago, Jeff-C175 said:

 

Wait... what the heck?  Is it Halloween already?

 

 

 

It's a Covid thing.

 

You missed the most important part, that mower tows without using wheels

[Jeff-C175 7,202]

1 minute ago, lynnmor said:

You missed the most important part, that mower tows without using wheels

 

I edited as you were posting!  

 

[Jeff-C175 7,202]

Not to change the subject, but I happened upon this whilst looking at the Flymo...  this is one of the most bizarre marketing photos I've ever seen.

 

 

I guess they're trying to say it's so quiet that it won't wake your sleeping baby, but shouldn't that baby have on some PPE? 

 

Or has it already been scared to death by the weed trimmer hovering over it's crib?

 

Or has it's right arm already been removed by the trimmer?  

 

 

Edited May 5, 2021 by Jeff-C175

[Lee1977 6,659]

2 hours ago, lynnmor said:

 

One of these of course:

 

That's his snapping turtle out fit. The cart that came with the mower is apart and stored, Here is another one with a rusted finish.

 

[Horse Newbie 7,069]

8 hours ago, Jeff-C175 said:

And there's no wheels on that mower!  Is that the "Flymo" version?

The wheels are under the deck for safety !...😝