Twin Strommies on 186

[FB_MAD]

Hi All.

A mate of mine has just fitted a twin X2 Stromberg type setup on a standard 186 and he is having problems with it running too rich.

He lives 2 1/2 hours from me so hard for me to go and have a look and I have never fiddled with X2 setups and am not familiar with how to modify the carbs to get them running effectively.

He is running a pair of BXUV-2 ,  1 3/32 carbs. I can only assume they are as fitted on a 138/149/161 Standard Red motor and are setup as they left the Holden factory.
He bought them "as is " on evilbay and the bloke told him they were from a running motor and were running fine ( no I don't believe that statement nor does my mate !!  )
I'd assume that fitting smaller main jets/ adjustable main jets would be a start and if so what size should I search for to start with??

Venturi Restrictors??

Pump plunger adjustment??

Anything else??

If anyone is running these carbs on a twin setup on a similar size standard or lightly modded Red Motor and doesn't mind giving up their carburetter setup and tuning secrets then could they help me out.

I've only ever used Holley and Weber Carbs on Modified Red Sixes years ago so am very much an amateur when it comes to  how to correctly setup Twin Strombergs and tune them to run properly, hence this post.

Any referals to someone who could help would also be appreciated as well.

Anyone know whether adjustable main jets are still available and where?

All constructive help very much appreciated.

Regards,

Terry.

[craiga]

I'd assume that fitting smaller main jets/ adjustable main jets would be a start and if so what size should I search for to start with??

Use 46's, possibly 50's if its a modified engine. American Autos in Sydney have adjustable jets available, but I found that they leaked.

Main jets will be a good start, set the linkages up so they are balanced and then use the mixture screws to set the idle mixture. Screw in until stumble, screw out until stumble, and then screw in until smooth. A manifold vacuum gauge will make this more accurate.

Grab a HD/HR manual and it will have full carby details of the factory setup.

Cheers,

Craig.

[FB_MAD]

Thanks Craig,

Haven't got a GMH  HD/HR  manual but have a Gregory's FX to HR one.

It lists the standard main jet for 149/161 as a 55  so if my mate's carbies are running 55's or bigger then that may explain at least some of the running rich problem.

If not I'll have to look elsewhere, maybe adjustable main jets if I can get some but I'd say a dyno would be needed to get them running correctly.

Tried to look up American Autos for adjustable mains/replacement mains but only some of their site is working.It mentions adjustable jets but no mention of availability, maybe a phone call is needed.

My mate is bringing the twin carb setup here on Saturday ( off the car at present ) so will do a post mortem on the carbs then and see if the linkages are opening the butterflys in unison equally.

Anyone else have any hints or ideas to add to Craigs help ??.

Regards,

Terry.

[Johns]

IMHO after lengthy experience with Italian twin carb systems, once you've checked simple stuff like, the dissy is operating properly, carby float levels are correct etc., the best way to sort this, is on a dyno

It saves guess work and will reveal other problems if they're there.

Cheers
John

[FB_MAD]

Thanks John for the reply.

Yep, I always start at the simple and cheap to repair items and go up in ascending order from there.

Helps with time management and the hip pocket as well!!.

Terry.