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Boomkidd

Junior Member
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Emerson, New Jersey
Hey all.
I was running the stock 668 carb and upgraded to the Walbro 990. It's ok... Every time I go to start it fresh, I always have to turn the low needle one full turn open, pull until I hear it begin to start and then put it back where it was. This is every time. Is there a different carb w/ a choke on it that's as good as the Walbro 990?

Thanks!
 
Boomkidd said:
Hey all.
I was running the stock 668 carb and upgraded to the Walbro 990. It's ok... Every time I go to start it fresh, I always have to turn the low needle one full turn open, pull until I hear it begin to start and then put it back where it was. This is every time. Is there a different carb w/ a choke on it that's as good as the Walbro 990?

Thanks!
Click to expand...
The Walbro 668 has exactly the same specs as the WT 990 but has a choke.
I bought a 990 and chucked it for the exact same reason starting as you're having and replaced it with the genuine Walbro WT668
The stocker is a 668 clone and nowhere near as good.
 
Phill said:
The Walbro 668 has exactly the same specs as the WT 990 but has a choke.
I bought a 990 and chucked it for the exact same reason starting as you're having and replaced it with the genuine Walbro WT668
The stocker is a 668 clone and nowhere near as good.
Click to expand...
Huh, I didn't even realize they cloned carbs. What do you think of the 1107? Seems to have a choke anyway.
I don't understand why some engineer felt the need to do away with it... I guess less air restriction.

1107: http://www.davesmotors.com/walbro-wt-1107-carburetor-585727601-zenoah.html
 
Boomkidd said:
Huh, I didn't even realize they cloned carbs. What do you think of the 1107? Seems to have a choke anyway.
I don't understand why some engineer felt the need to do away with it... I guess less air restriction.

1107: http://www.davesmotors.com/walbro-wt-1107-carburetor-585727601-zenoah.html
Click to expand...
I have the Walbro 990 and 1107. They both do well. The 990 seems to have a little more punch but not a ton. The 1107 is alot easier to start. 2 pulls on choke 2-3 more no choke and it is idling. The 990 I have found 3-4 slow pulls then 3-4 fast pulls and it is ilding. In the warmer months the 990 is much easier to start.
 
G-Man said:
I have the Walbro 990 and 1107. They both do well. The 990 seems to have a little more punch but not a ton. The 1107 is alot easier to start. 2 pulls on choke 2-3 more no choke and it is idling. The 990 I have found 3-4 slow pulls then 3-4 fast pulls and it is ilding. In the warmer months the 990 is much easier to start.
Click to expand...
Gotcha. The only way I have been able to start my 990 from cold start is turn low needle open 1 full turn, pull like 2 times until it begins to sputter, turn needle back to where it was pull and it starts. I have not been able to do it w/o moving the needle which to me is a bit annoying. But hmm, if the 990 is a little punchier, may stick with it. Not sure. Sometimes after idling for a while, when I give it gas it bogs for like a millisecond it seems where it transitions from low to high needle. Only if it idles for like 30 secs + though. No big deal, just don't really like those 2 things is all.
 
Boomkidd said:
Gotcha. The only way I have been able to start my 990 from cold start is turn low needle open 1 full turn, pull like 2 times until it begins to sputter, turn needle back to where it was pull and it starts. I have not been able to do it w/o moving the needle which to me is a bit annoying. But hmm, if the 990 is a little punchier, may stick with it. Not sure. Sometimes after idling for a while, when I give it gas it bogs for like a millisecond it seems where it transitions from low to high needle. Only if it idles for like 30 secs + though. No big deal, just don't really like those 2 things is all.
Click to expand...
The 4 slow pulls on the 990 is key. It puts the fuel into the engine. I am able to start mine in 20 degree weather. Some guys will put a baggie over the air filter for the first 2 pulls acting as the choke. The bog issue is the plug starting to fowl out with fuel. Doesn't take long for a 2 stroke to load up idling. One thing I do suggest is the Team Chase primer bubble filter. I just got 2 of them for both of my rigs. I killed my first 990 in 7 months allowing the dirt in through the hole for the bubble. Ddm has them
 
G-Man said:
The 4 slow pulls on the 990 is key. It puts the fuel into the engine. I am able to start mine in 20 degree weather. Some guys will put a baggie over the air filter for the first 2 pulls acting as the choke. The bog issue is the plug starting to fowl out with fuel. Doesn't take long for a 2 stroke to load up idling. One thing I do suggest is the Team Chase primer bubble filter. I just got 2 of them for both of my rigs. I killed my first 990 in 7 months allowing the dirt in through the hole for the bubble. Ddm has them
Click to expand...
I usually do 2 slow pulls and then open the low needle. I read about the baggie thing but won't do that. 990 prob has 5 tanks on it. Plug looks pretty clean and only has like 5 tanks or so through it also (NGK plug.) Doesn't bog after hitting the throttle. It only bogs after letting idle for 30 or more seconds is all. May be loading up. Guess I'll scoop up another plug... I'll need it sooner or later anyway.
Thanks man.
 
Boomkidd said:
I usually do 2 slow pulls and then open the low needle. I read about the baggie thing but won't do that. 990 prob has 5 tanks on it. Plug looks pretty clean and only has like 5 tanks or so through it also (NGK plug.) Doesn't bog after hitting the throttle. It only bogs after letting idle for 30 or more seconds is all. May be loading up. Guess I'll scoop up another plug... I'll need it sooner or later anyway.
Thanks man.
Click to expand...
I don't know where you are from but I have Advanced Auto Parts stores all around me. They carry the NGK CMR7H Plugs cheap and honor a warranty on them. Every 3 or 4 tanks I pull the plugs and swop them out with fresh ones for free. The whole turning the needle all the time sucks to get your truck to start. Probably isn't good for the carb to do that either. You ever try to turn your idle screw up a hair for initial starting?
 
G-Man said:
I don't know where you are from but I have Advanced Auto Parts stores all around me. They carry the NGK CMR7H Plugs cheap and honor a warranty on them. Every 3 or 4 tanks I pull the plugs and swop them out with fresh ones for free. The whole turning the needle all the time sucks to get your truck to start. Probably isn't good for the carb to do that either. You ever try to turn your idle screw up a hair for initial starting?
Click to expand...
I haven't tried the idle screw but I do goose the throttle while pulling it as well. I'm in New Jersey and there's a lot of like every store here including Advance. Autozone and Pepboys are a lot closer though. But damn if advance does a warranty I think I know where I'll go lol. I truly didn't realize one should be changing the plug out that frequently. I only initially got rid of the factory poop plug because the T/B servo started twitching out one day only while running. NGK plug fixed it like magic.
Thanks once again dude!
 
Boomkidd said:
I haven't tried the idle screw but I do goose the throttle while pulling it as well. I'm in New Jersey and there's a lot of like every store here including Advance. Autozone and Pepboys are a lot closer though. But damn if advance does a warranty I think I know where I'll go lol. I truly didn't realize one should be changing the plug out that frequently. I only initially got rid of the factory poop plug because the T/B servo started twitching out one day only while running. NGK plug fixed it like magic.
Thanks once again dude!
Click to expand...
No real need to change the plug that often, I just do it because they are warranty and why not. Makes the start up so much easier
 
There is no need to change the spark plug that soon. If your carb is setup properly, your spark plug will last a long time.

As for issues with the 990, it's a more sensitive carb. Very tiny needle adjustments are required to get to the right spot for it. You turn two much (or as you would with a 668) then you may go from having too much fuel to lacking some and vice versa.

I have 2 Walbro 668, 1 668 clone , 2 990 and 2 1107. The 990 shows a more agressive side when it comes to power (when well tuned).

Starting requires 1 or 2 things:

- 2-3 slow pulls or
- bag or over filter

In optimum weather none of the above is required.
 
Boomkidd said:
Gotcha. The only way I have been able to start my 990 from cold start is turn low needle open 1 full turn, pull like 2 times until it begins to sputter, turn needle back to where it was pull and it starts. I have not been able to do it w/o moving the needle which to me is a bit annoying. But hmm, if the 990 is a little punchier, may stick with it. Not sure. Sometimes after idling for a while, when I give it gas it bogs for like a millisecond it seems where it transitions from low to high needle. Only if it idles for like 30 secs + though. No big deal, just don't really like those 2 things is all.
Click to expand...

That's why I chucked mine.
If you read the specs the668 is the exact same carb with a choke.
The 1107 works best on 32cc
 
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