Stop the Pop

[23 Reo 229]

My K321 runs good but has a bit of a pop through the rpm range. Could it be an intake leak?

[ebinmaine 67,435]

Check for a loose carb throttle shaft. 

With the engine off turn the throttle to about 3/8 or 1/2. 

See if there's a wiggle in the clearance from shaft to body.  

 

Very common. Usually repairable with Hillman washers and the correct removal method.  

I use a Dremel to grind the backs of the screws off. 

 

 

[23 Reo 229]

What size Hillman washers and what do they look like?

[ebinmaine 67,435]

16 minutes ago, 23 Reo said:

What size Hillman washers and what do they look like?

 

I keep these part numbers in my notes.   

 

Carb copper washers:

MMC  #  5906K561

 

Or 

Hillman 58087

[ebinmaine 67,435]

You're welcome to send that carb up to me and I'll rebuild it for you 

[23 Reo 229]

Thank you Eric. I'm pretty sure the rebuild parts are fairly fresh but I may take you up on that. I think it is the original carb.

[ebinmaine 67,435]

3 minutes ago, 23 Reo said:

Thank you Eric. I'm pretty sure the rebuild parts are fairly fresh but I may take you up on that. I think it is the original carb.

I'd be happy to help if I can. Just PM me for my address.

 

If those parts are more than a year or two old and you are still using ethanol gasoline they probably aren't much good anymore.

I've been seeing some serious short-term damage on the square cut gasket for the bowl, along with the interior baffle.

Edited November 21, 2023 by ebinmaine
Correct autocorrect which is supposedly smarter than me

[23 Reo 229]

Will do,

[gwest_ca-(File Mod) 11,040]

Try a shot of Marvel Mystery oil in the fuel. It will lubricate the valve stems and help to ensure the valves move as fast as required.

Have had the same results using 2-stroke oil.

[ebinmaine 67,435]

48 minutes ago, gwest_ca said:

Try a shot of Marvel Mystery oil in the fuel. It will lubricate the valve stems and help to ensure the valves move as fast as required.

Have had the same results using 2-stroke oil.

How much do you use ? 

[gwest_ca-(File Mod) 11,040]

Probably start with 2 oz. per tank for a couple of tanks full then 1/2 oz. per tank.

[peter lena 8,610]

@gwest_ca   @ebinmaine @23 Reo  totally agree with the fuel additive , running in a used engine , want to add KROIL , to that fuel , talk about a crud cutter !  often use a separate gallon of  fuel , on a used engine . fast idle , look / listen , good time for a hot oil flush ,  add , RISLONE , zinc  , about 4 oz. , for 2 qts oil , drop carb bowl , etc. . very good base line service , obviousely other issues , but  its , really made changes to engines that I have picked up , pete

[23 Reo 229]

I've had great luck with Kroil for loosening bolts. I still have PB Blaster but Kroil works better in my opinion.

Edited November 23, 2023 by 23 Reo

[ebinmaine 67,435]

1 hour ago, 23 Reo said:

I've had great luck with Kroil for loosening bolts. I still have PV Blaster but Kroil works better in my opinion.

 

IMHO and with all due respect to those who use it...

I believe PB Blaster is only worth anything because of excellent marketing.  

I've never been a fan.  

Multiple products have been shown over and over to be superior.   

 

[23 Reo 229]

I use an ounce per gallon of Sea Foam in all my fuel. Does that help clean the top end?

[Bill D 1,920]

18 hours ago, gwest_ca said:

Try a shot of Marvel Mystery oil in the fuel. It will lubricate the valve stems and help to ensure the valves move as fast as required.

Have had the same results using 2-stroke oil.

Can you achieve the same results using 50:1 2 cycle mix?

[c-series don 8,689]

I’m not sure if 50:1 will do the same as Marvel Mystery Oil? I add an ounce or two of MMO per tank randomly, might smoke a little bit but I believe it’s good for the valves and rings. Or maybe it does nothing but make me feel like I’m taking care of my engines? 😂

[Jon Paulsen 290]

On 11/23/2023 at 6:52 AM, c-series don said:

I’m not sure if 50:1 will do the same as Marvel Mystery Oil? I add an ounce or two of MMO per tank randomly, might smoke a little bit but I believe it’s good for the valves and rings. Or maybe it does nothing but make me feel like I’m taking care of my engines? 😂

Been doing the same for eons. 0 carb issues. Well, except the Thanksgiving carbs I eat 

[peter lena 8,610]

@23 Reo   been using RISLONE  ZINK , ZDDP , in my oils for years , measurement for 2 qtr. oil is 4 oz. RISLONE . bottle specs , use a small measuring cup . talk about engine cleaning /  ring flush , zero engine smoke , also use ROTELLA  30WT oil , no mixture issues / at all , engines also run easier / smoother , use this in 5 small engines , been a very good gain for me . makes newer oils work in older engines, price shop , hot oil flushes , verify cleaning effects . Pete