[Fot] Fwd: Stutter at 4K rpm

[toodamnfunky at comcast.net]

May be time to look at the accelerator pump. My brother had a similar issue with his 40 IDF's. He WAS using gas with ethanol 
and it was leaving crusty deposits in the carbs every race & now buys non-ethanol ( av-gas ). 
jim g 

----- Original Message -----

From: "D V" <explore8 at outlook.com> 
To: "Scott Barr" <sbarr at McCarty-Law.com>, "fot" <fot at autox.team.net> 
Sent: Sunday, October 16, 2016 9:14:15 PM 
Subject: Re: [Fot] Fwd: Stutter at 4K rpm 

Thanks again everyone. I checked the header to head and the exhaust to header connection and everything seemed tight. However I went 2 off hard at turn 4 this morning and my strap that was holding the exhaust is now mostly gone. I never figured out that 180 degree off camber turn all weekend. 

To answer Scott's question, yes. I can brake downshift to 3rd in a turn. Full on the gas out of the turn and it stutters between 4-5k. If I do the same and ease into the gas I can most of the time keep it steady. 

Re working the exhaust system as well as checking the float will be added to my winter maintenance. 

Sent from my iPhone 

> On Oct 16, 2016, at 2:21 PM, Barr, Scott <sbarr at McCarty-Law.com> wrote: 
> 
> Is it temporary? Just as you get on the gas out of a corner and then clears up as the revs rise? 
> 
> If so, do you have no oil in your dashpots or have you removed the dashpot pistons? 
> 
> Scott (B.) 
> 
> 
> 
> 
> 
> -------- Original message -------- 
> From: D V <explore8 at outlook.com> 
> Date: 10/16/16 12:53 AM (GMT-06:00) 
> To: Greg Blake <gblake58tr3 at icloud.com>, fot at autox.team.net 
> Subject: Re: [Fot] Fwd: Stutter at 4K rpm 
> 
> Thanks everyone for the replies. I will inspect the pipe to manifold and manifold to head to see if anything is loose or any leaks apparent in the morning. 
> 
> I actually went down a main jet 145 to 140 and that seemed like it helped some but didn't clear up the issue (which is going leaner; opposite of what Greg said). 
> 
> It is missing and backfiring when I am full on the gas. I can prevent it by easing into the gas. 
> 
> I did notice some gas at my air cleaner to velocity stack connection. I wonder if it is a float issue? 
> 
> 
> Sent from my iPhone 
> 
> On Oct 15, 2016, at 7:35 PM, Greg Blake <gblake58tr3 at icloud.com<mailto:gblake58tr3 at icloud.com>> wrote: 
> 
> Don't know if my other email made it to you. Backfires on deceleration can be a lean condition. Have you checked your plugs? Maybe something got "adjusted" with the bump. 
> 
> Sent from my iPhone 
> 
> On Oct 15, 2016, at 12:27 PM, D V <explore8 at outlook.com<mailto:explore8 at outlook.com>> wrote: 
> 
> 
> 
> Sent from my iPhone 
> 
> Begin forwarded message: 
> 
> From: <explore8 at outlook.com<mailto:explore8 at outlook.com>> 
> Date: October 15, 2016 at 10:30:51 AM CDT 
> To: <fot at autox.team.net<mailto:fot at autox.team.net>> 
> Subject: Stutter at 4K rpm 
> 
> Two races ago I went off track and bent my exhaust pipe enough to break the welded joint near the muffler. In the interest of time, I cut the exhaust at the muffler and secured the pipe to the frame. 
> 
> At the last race, I noticed the car would backfire at deceleration which I am not surprised but I also noticed a stutter around 4-5k rpm. 
> 
> At NOLA this weekend it is more pronounced and comes in when shifting hard from 3rd to 4th. After 5k, it clears up and pulls normally. 
> 
> It doesn't seem to be affected by turns and more related to full throttle vs easing into the gas. 
> 
> Backpressure from the loss of muffler or unrelated issues? 
> 
> 1300 spitfire with single Weber 40. 
> 
> Sent from my iPhone 
> _______________________________________________ 
> fot at autox.team.net<mailto:fot at autox.team.net> 
> 
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