9 replies to this topic

[TotemoToi]

Mates,

 

Got a 92 998 with a Weber DCOE 40 and FET intake.  Engine/exhuast is stock except for an upgraded high flow muffler.  Previous owner ran F8 45 idle jets in winter from Nov to April, and F8 40s from May to Sept is seems but he wasn't 100% about the summer ones or if this combo was ideal.  With the 45s it ran decent (albeit taking 5 minutes or so to warm up and have the initial gas pedal blip clean up (just a slight bog down from idle to 1500rpm for the first 5 minutes warming up, which I assume is normal. It wouldn't bog down as long as I just gently gave it gas from 900-1500 though).  Idling was around 900rpm and stabilized once warmed up.

 

I put in the 40s recently, and I am getting a bit more of a bog if I give it a good blip of gas while warming up, but then it cleans up beyond 1500-2000rpm or so.  Seems like I have be much more gentle from 900-1500 in comparison to the winter jets.  It does seem like a bit less power though, but seems to be idling smoother.  Also, once the weather got warm, the engine starts to make a bit of a tapping sound, but now that seems gone with the summer jets.

 

MY QUESTIONS:

 

1. Does this set up seem good?

2.  I'm just wondering if everyone does this (different idle jets for summer/winter) and if I am using the correct jets.

3.  Also, is the stutter from 900rpm-1500 normal for first 5 minutes of warming up both in summer and winter? 

4.  In summer, should I try starting w/ no choke or half perhaps?  It does start up okay, but not right away a does require a bit of pumping before and after ignition starts.

 

By the way, I live in a place with a quite hot summer, and a mild winter.  Average coldest month is 9C (doesn't snow here) and average warmest is 32C.

 

Cheers in advance for any info mates!

 

 

 

 

[Dusky]

1) maybe
2) Never ever needed to do that on any car with a weber I've seen
3) no and yes, just sounds like your choke isn't adjusted properly.
4) Use the choke. You don't need to pump the gas with a properly adjusted choke.

[TotemoToi]

1) maybe
2) Never ever needed to do that on any car with a weber I've seen
3) no and yes, just sounds like your choke isn't adjusted properly.
4) Use the choke. You don't need to pump the gas with a properly adjusted choke.

Thanks for the info!  Yeah, I've never heard of it before either.  I'm not sure about the choke.  Seems to work properly...what I mean is once I push the choke back in (no choke), I have a bogging down throttle response stutter from 900-1500 or so if I give too much gas for first 5-10 minutes as car is still warming up.  But that's even in the summer too, so I was thinking an idle jet issue because throttle response from 900 is what that controls specifically. And in fact the F840 I am supposed to use in summer (as what the previous owner told me) doesn't seem right either since I found the F845 to cause a bit less of the stutter.

 

So, I'm just wondering if I should just try out a variety of jets.  I mean, the car ran pretty good on the F845, just took a bit to start up, and would bog down a bit in winter for 5-10 minute from 900-1500.

 

Any other ideas? Cheers!!!

 

[Dusky]

1) maybe
2) Never ever needed to do that on any car with a weber I've seen
3) no and yes, just sounds like your choke isn't adjusted properly.
4) Use the choke. You don't need to pump the gas with a properly adjusted choke.

Thanks for the info! Yeah, I've never heard of it before either. I'm not sure about the choke. Seems to work properly...what I mean is once I push the choke back in (no choke), I have a bogging down throttle response stutter from 900-1500 or so if I give too much gas for first 5-10 minutes as car is still warming up. But that's even in the summer too, so I was thinking an idle jet issue because throttle response from 900 is what that controls specifically. And in fact the F840 I am supposed to use in summer (as what the previous owner told me) doesn't seem right either since I found the F845 to cause a bit less of the stutter.

So, I'm just wondering if I should just try out a variety of jets. I mean, the car ran pretty good on the F845, just took a bit to start up, and would bog down a bit in winter for 5-10 minute from 900-1500.

Any other ideas? Cheers!!!

How long do you leave the choke on?
It's more than just a cold start device, on some other cars I have that are equipped with double 40 dcoe webers from factory, the choke automatically turns on and off slowly when warming up.

[TotemoToi]

 

 

1) maybe
2) Never ever needed to do that on any car with a weber I've seen
3) no and yes, just sounds like your choke isn't adjusted properly.
4) Use the choke. You don't need to pump the gas with a properly adjusted choke.

Thanks for the info! Yeah, I've never heard of it before either. I'm not sure about the choke. Seems to work properly...what I mean is once I push the choke back in (no choke), I have a bogging down throttle response stutter from 900-1500 or so if I give too much gas for first 5-10 minutes as car is still warming up. But that's even in the summer too, so I was thinking an idle jet issue because throttle response from 900 is what that controls specifically. And in fact the F840 I am supposed to use in summer (as what the previous owner told me) doesn't seem right either since I found the F845 to cause a bit less of the stutter.

So, I'm just wondering if I should just try out a variety of jets. I mean, the car ran pretty good on the F845, just took a bit to start up, and would bog down a bit in winter for 5-10 minute from 900-1500.

Any other ideas? Cheers!!!

How long do you leave the choke on?
It's more than just a cold start device, on some other cars I have that are equipped with double 40 dcoe webers from factory, the choke automatically turns on and off slowly when warming up.

 

In winter, maybe a minute or two, and then it can idle on it's own.  In nice weather, just to get it started, and then shut it off right away and it can idle on it's own, but it just stumbles from 900-1500 for first 5 minutes if I don't really baby the throttle.  That help???

[nicklouse]

Sounds like it has never been on a rolling road to be set up correctly. I would also say it is very over carbed.

[1968andyf]

The numbers 40 and 45 are the fuel hole f9 is air holes suggest using a 45f2 same fuel less air then adjust with the idle mixture screw

[Dusky]

1) maybe
2) Never ever needed to do that on any car with a weber I've seen
3) no and yes, just sounds like your choke isn't adjusted properly.
4) Use the choke. You don't need to pump the gas with a properly adjusted choke.

Thanks for the info! Yeah, I've never heard of it before either. I'm not sure about the choke. Seems to work properly...what I mean is once I push the choke back in (no choke), I have a bogging down throttle response stutter from 900-1500 or so if I give too much gas for first 5-10 minutes as car is still warming up. But that's even in the summer too, so I was thinking an idle jet issue because throttle response from 900 is what that controls specifically. And in fact the F840 I am supposed to use in summer (as what the previous owner told me) doesn't seem right either since I found the F845 to cause a bit less of the stutter.

So, I'm just wondering if I should just try out a variety of jets. I mean, the car ran pretty good on the F845, just took a bit to start up, and would bog down a bit in winter for 5-10 minute from 900-1500.

Any other ideas? Cheers!!!

How long do you leave the choke on?
It's more than just a cold start device, on some other cars I have that are equipped with double 40 dcoe webers from factory, the choke automatically turns on and off slowly when warming up.

In winter, maybe a minute or two, and then it can idle on it's own. In nice weather, just to get it started, and then shut it off right away and it can idle on it's own, but it just stumbles from 900-1500 for first 5 minutes if I don't really baby the throttle. That help???

You surely could try leaving the choke a bit longer. On the stradas it's about 10 minutes of choke in winter

[TotemoToi]

The numbers 40 and 45 are the fuel hole f9 is air holes suggest using a 45f2 same fuel less air then adjust with the idle mixture screw

Okay, cheers.  Will try!

[TotemoToi]

 

 

 

 

1) maybe
2) Never ever needed to do that on any car with a weber I've seen
3) no and yes, just sounds like your choke isn't adjusted properly.
4) Use the choke. You don't need to pump the gas with a properly adjusted choke.

Thanks for the info! Yeah, I've never heard of it before either. I'm not sure about the choke. Seems to work properly...what I mean is once I push the choke back in (no choke), I have a bogging down throttle response stutter from 900-1500 or so if I give too much gas for first 5-10 minutes as car is still warming up. But that's even in the summer too, so I was thinking an idle jet issue because throttle response from 900 is what that controls specifically. And in fact the F840 I am supposed to use in summer (as what the previous owner told me) doesn't seem right either since I found the F845 to cause a bit less of the stutter.

So, I'm just wondering if I should just try out a variety of jets. I mean, the car ran pretty good on the F845, just took a bit to start up, and would bog down a bit in winter for 5-10 minute from 900-1500.

Any other ideas? Cheers!!!

How long do you leave the choke on?
It's more than just a cold start device, on some other cars I have that are equipped with double 40 dcoe webers from factory, the choke automatically turns on and off slowly when warming up.

In winter, maybe a minute or two, and then it can idle on it's own. In nice weather, just to get it started, and then shut it off right away and it can idle on it's own, but it just stumbles from 900-1500 for first 5 minutes if I don't really baby the throttle. That help???

You surely could try leaving the choke a bit longer. On the stradas it's about 10 minutes of choke in winter

 

Sure.  It's not really winter that's the issue.  It's just when I changed the jets this summer to what the previous owner suggested that the stumbling became bad.  I might just go back to the "winter" idle jets and just stick with that b/c the car seems to have better throttle response and wouldn't bog down so much.  Or maybe experiment w/ some other jets like the other poster suggested.  I think perhaps the previous owner just didn't know *******.  Perhaps I dunno *******!  Lol.  That's why I'm here!  New to Webers.  Meh, I probably need to get myself a whole jet set and test and test and test, but I was just wondering if anyone out there had a stock 998 with a Weber 40, and what works for them so I can avoid all the hassle, you know?  Anyway, cheers for the advice!