Backwards carb

[JasonB]

I'm still working on the carb upgrade on my 888 mercruiser. I'm going from a 2bbl rochester to a 4bbl weber. The weber is a square bore and the intake is a stock cast one.<br /><br />I've run into a problem with the trottle cable. The Rochester gets pushed open by the cable, the weber is pulled open. My control box cannot be reversed. <br /><br />The fuel inlet is also on the opposite corner of the carb from the engine's fuel pump.<br /><br />Dumb question... what would happen if one installed the carb backwards (idle screws to the rear, secondaries toward the front)? <br /><br />I'm getting too irritated with this swap.....

 

[Don S]

Re: Backwards carb

Why don't you just go to the throttle and shift mechanism at the helm and change the cable to operate the correct way.

 

[JasonB]

Re: Backwards carb

Tried that Don. It looks like I would have to replace one of the cam plates to make it work with my Mercontrol, unless I missed something?<br /><br />It is a '76 standard panel mount Mercontrol without trim. I was able to move the shaft the roller fits on and rotate the cam plate 180 deg, but the track in the cam plate just didn't fit properly.<br /><br />I looked at the panel mount control diagrams at oug Russel, but none look right.

 

[JasonB]

Re: Backwards carb

I think I have a 37782a1-2<br /><br />"http://www.stemtostern.com/MercIndex/GetDiagram.asp?collection=09&docs=REMOTE%20CONTROLS&serial=Mercruiser%281985%20and%20Below%29&part=60&block=2182"

 

[Don S]

Re: Backwards carb

I don't see many of those controls anymore, and I never tried to make one go the other direction. But turning the carb around is completely off base.<br />You may have to make your own linkage to work from the opposite side of throttle shaft and mount it on to the existing linkage. But hey, you want to do something out of the ordinary, then you have to deal will all the details to get it to work properly.

 

[JasonB]

Re: Backwards carb

Thanks for the info Don. The backwards mounting was more of a question of what would happen and not really something I wanted to do. Everything about this upgrade has been a challenge in some way, so I was trying to be light hearted about it and "think outside the box".<br /><br />I was pondering the hole on the bottom of the existing plate on the throttle shaft and the odea of making an extension foir it so it would have the same travel as the top pull , just not sure what to do at the moment that will work and be safe. Even considered flipping the throttle bracket to the front so teh cable sould push teh caebb throttle open, but that woul dbe messy at a minimum.

 

[bigbrownbuku]

Re: Backwards carb

mount the carb conventionally. run the cable at the carb from the other direction, you may have to fashion a new cable mount and/or buy a slightly longer cable.

 

[paulie0735]

Re: Backwards carb

This is an interesting thread…………..I noticed a rod a few months ago that had carter carbs (basicly the same as the weber) mounted backwards on a dual carb set up and it ran just fine. I see no issue mounting it backwards and would love for somebody to explain why it’s a problem, unconventional? Yes, but that doesn’t mean it won't work. I don’t accept that g’force will hinder its performance as carbs are designed to work under all kinds of stress re cornering and braking so I really can’t see the problem, in fact in old rally cars they will even work upside down.

 

[Bondo]

Re: Backwards carb

Hot Rods aren't sitting at an Angle,... Like a Boat......<br /><br />I'm Sure that Finding the proper Float Level would be a Real Problem......<br />After All,.... The Floats will be hinged from the Wrong End.......<br /><br />I think changing the Linkage would be Easier than turning the Carb around........

 

[rodbolt]

Re: Backwards carb

well ya just cant have gas flowing backwards .<br />as long as its a square bore carb and the intake is a square bore you can mount it backwards,holley makes a kit to mount it sideways.<br /> however your still stuck with making brackets,adapters and fuel lines.<br /> in the end your not gonna see any real gains, the money would have been better spent on maint and refresing beverages.

 

[JasonB]

Re: Backwards carb

Looks like I provoked some thought <br /><br />It looks like I have 4 options<br /><br />1. give up and run for the hills (not my style, but appealing)<br /><br />2. Buy a new control box (not in the budget, though I would love to have trim on teh throttle handle...)<br /><br />3. do as BenC suggested and mount the throttle bracket on the front of the carb and let it push the throttle open from the front - appealing for its apparent simplicity, but I wonder about the distance from teh bracket arm to the carb throttle being too close. I have the bracket that was used on the 225 engine (302/4bbl) from Mercruiser<br /> <br />4. Use the bottom hole on the carb throttle. I really like this idea, but after reading this post: Linkage post , I have the same carb and would be using teh same hole, and likely to run into the same issue. May just have to try and fab an extension for that.

 

[JasonB]

Re: Backwards carb

Well, as much as I hate to admit it, I ended up going with option #5.....<br /><br />I went out to tinker with the linkage to see if I could make an adaptor plate or something, only to find that the old carb IS pull linkage, not push. So in summary, I did all this due to not double checking the simple things..... <br /><br />I shoul now have a big red handprint on my forehead from smacking myself upside the head for being that stupid.....<br /><br />On a positive note, the new manifold and carb are a great fit, I just have to finish attaching the linkage and changing the connectors for the choke.