Looking to replace mikuni carburetor with weber.

[Cdukes96]

I have a 1987 dodge ram 50 and I'm looking to replace the mikuni carburetor with a weber but im not sure which model I need because I don't know where the throttle linkage is. If anyone could help me find a place to buy the correct carburetor as well as a conversion kit I'd be extremely grateful.

[SubGothius]

Either a DFEV or DGEV Weber 32/36 will work. The DFEV is slightly preferable for easier throttle cable routing with the fuel float bowl placed in front. The DGEV is more readily available and tends to be cheaper, but poses a dilemma of easy cable routing with the float bowl at the rear vs. trickier cable routing with the bowl in front.

Float bowl in the rear makes it run slightly rich braking or going downhill and slightly lean accelerating and going uphill, which is the opposite of what's preferable, but it's not that big a deal. I happen to run a DGEV on my '87 2.6L just fine for the most part, and I just try to brake gently and well in advance whenever possible, though I sometimes stall out on abrupt/panic stops.

The Redline Weber kit K610 includes a DGEV, and their kit K614 includes a DFEV. The latter is necessary if you've got an auto trans, as that allows for a kickdown linkage, but a manual trans can use either one. These kits are available directly from Redline Weber (who seem to be the main US Weber distributor), who also supply them to Pierce Manifolds and Carbs Unlimited (carburetion.net).

If you don't buy new from one of those official Weber/Redline distributors, at least take care to get a genuine Weber made in Spain, not one of the Chinese-made clones offered by EMPI and others. They're "licensed" clones in general design and name/logo only, but they aren't finished to the same exacting tolerances as genuine Webers, so they often can't be tuned to run properly in all conditions. Genuine Webers have a slightly dull/rough looking finish, with the Weber name/logo and "Made in Spain" cast right into the body, and usually have a translucent-off-white electric choke cover. Clones have a bright/smooth finish, with the Weber name/logo only as a decal, tag, or ink stamp, and usually have a black choke cover.

That said, the electric choke cover isn't always a dead giveaway, especially for secondhand carbs, as it's possible to install either choke element on any Weber -- e.g., using the cloned choke element to to upgrade a genuine Weber's original water choke to electric, or using a genuine choke element on a clone to make it look more genuine.

[Cdukes96]

Thanks so much for the reply, I appreciate it. I will look into both options and hopefully be able to find them no problem. Ill update the thread with everything as it unfolds. Once again, thank you for your help.

[Cdukes96]

I'm about ready to replace the mikuni with the weber, but I have a question. What's going to happen to all those vacuum hoses? Or am i just going to have to plug them off?

[SubGothius]

The swap will eliminate most vac hoses. Leave all hoses attached to the old carb and the control box mounted to the driver's inner fender, and pull them both out together along with their hoses, detaching any hose ends that aren't connected to the carb or control box. IIRC, those would be the ends connected to a thermovalve or two, the "tree" of barbs screwed into the intake manifold below the carb, and some hose connectors near the firewall.

The only vac hoses you really need to retain are for the brake booster (which isn't connected to the carb anyway) and your distributor vacuum advance. If you don't have emissions testing, you can connect the vac advance to one of the barbs on that manifold tree. Then use short loops of hose to cap pairs of the remaining open barbs on that tree, as hose is cheaper and more durable than caps, so you'd only use 1 cap if there's an odd-man-out barb remaining.

DRAIN THE COOLANT at least partially before removing the stock carb. There's a coolant port in the carb mounting flange on the manifold, which will overflow into the manifold if you don't drain coolant first. I think the Redline adapter plate should block that port, but it's advisable to tap it for threads to block with a stainless grub screw (M6 or M8, I forget which). I'd recommend tapping that port just deep enough for the screw to clear the carb mounting face when screwed down tight, and use a high-temp thread sealant (e.g. Permatex 59214).

There's also a coolant tee in the intake manifold behind the carb, which feeds the stock carb's water choke. You'll need to either remove that tee and replace it with a single-barb fitting, or cap the unused barb with a short length of hose blocked with a bolt at one end, secured with hose clamps at both ends.

[Cdukes96]

I was wondering about that tee. The only part I'm really stuck on now would be the electrical connection that was on the old carb. It's a big black plug that had one wire that went to the choke. I'm looking now but I'm not too sure where to connect the choke to now.

[geezer101]

That wire goes to the electric choke on the Weber. It's only live when the engine is running and depending on the generation of truck, the purpose of that connection is to either run the fuel cut solenoid or the electric choke (it's bridged into the ignition coil circuit)

[SubGothius]

Or if you'll run an electric fuel pump on a relay, that wire would trigger the relay, and the relay would switch power directly from the battery (+) terminal to the pump and electric choke.

[Cdukes96]

I just tried to fire it up for the first time and I cant get it to start. I'm not sure what I did wrong. I'm sure it's something simple, but its throwing me for a loop.

[Cdukes96]

I think I may have the fuel lines in the wrong spot. I have the stock mechanical fuel pump on it and I put the supplied hose from the port thats the highest and also the biggest on the pump to the carb when I think its supposed to be the curvy port to the carb. While the one that's kind of in the middle is the return amd needs to be plugged. Does that sound right? I'll see if I can upload a picture of what I have.

[Cdukes96]

Got it figured out! I got so excited when it fired up. I am by no means an expert at this and felt so accomplished getting it done. Thank you for all your help subgothious and geezer.

[geezer101]

A cautionary tale - expect grief if you are running the Weber off the factory mechanical fuel pump. It will over pressurize the fuel float and cause running issues. Trying to rectify it with a fuel pressure regulator will eventually result in the mechanical pump failing. Only way to solve this is to run an electric high volume low pressure pump (HVLP) that can handle up to 42 gallons per hour. Guys have used Carter P4070 rotary vane pumps - I have done so and had to deal with excessive noise and pump failure (these things aren't cheap either) Mr Gasket sells their 42S pump which will work well but the same pump is sold under the Carbole label for almost half the price of the Mr Gasket pump.

That being said - congrats on getting it up and running

[94maxlow]

I'm attempting to install a Weber k 614 32/36 on my 2.6 with 5 speed. This kit did not include a block off plate between the carb and the intake. Does anyone know were i could find one. I'm really thinking about starting my own thread ( manly so i don't hijack another members).

Anyone have any other thread suggestions or can tell me what all I'm going to need. I was very naive in thinking this would just bolt down and run. The research i have done so far has led me to, adding a electric fuel pump / blocking manual fuel pump. What else am i missing??

[SubGothius]

This kit did not include a block off plate between the carb and the intake.

Do you mean the adapter plates to adapt the stock carb bolt pattern to the Weber bolt pattern? That should have been included in the K614 kit as a standard part. If you got the kit from an proper vendor like Redline Weber, Pierce Manifolds, or Carbs Unlimited (carburetion.com), contact them to say they sent you a kit missing the adapter plates.

If you meant a plate to block off the hole in the head where you removed the stock mech fuel pump, you can use a fuel pump block-off plate for a classic Chevy big-block V8, Ford big/small block V8, Mopar V8. This is the diamond-shaped 2-bolt plate, not the 4-bolt plate for Chevy small-blocks. Some minor modification may be required (e.g. filing down a bit of the two longer sides), so get an alloy plate rather than the steel version.

[94maxlow]

Thanks for your reply SubGothius, I received the plate to bolt the carburetor to the intake. I was thinking since the stock carburetor is a water choke that the holes in the intake under the carburetor would need to be covered by a plate.

[94maxlow]

Hopefully the photos will show up. The holes I circled in red are the ones i was needing to know if they need a plate or not?

[SubGothius]

The middle small hole on the left is the jet-valve intake port, which only works with the stock carb. The adapter plate should block that, but I'd also advise disabling the jet valves by removing their lash-adjuster screws from the rockers under the valve cover, or you could even install a jet valve eliminator kit that replaces the jet valves.

The middle small hole on the right is the coolant port for the stock carb's water choke, which should also be blocked by the adapter plate, but I'd also advise tapping that hole for threads to block it with a grub screw, as described above in this thread.

[94maxlow]

I'm referring to the two big holes. Do they need to be covered with a plate or is it ok to have them open?

[SubGothius]

Those are where the intake manifold receives an intake charge from the carburetor -- i.e., the carb mates up to the manifold there, so the bottom end of the carb barrels feed directly into those big holes.

The Weber adapter plates mount on top of that flange, between the manifold and carb, to convert the size and position of those holes to the slightly differing size/position of the Weber barrels, as well as converting the stock hold-down bolt pattern in the manifold to the mounting bolt-hole pattern in the base of the Weber.

BTW, looks like you got some coolant overflow into the intake manifold there, so you'll want to mop or vacuum that up before installing the new carb and trying to start it up.

[94maxlow]

See that is what i was confused about. When i pulled the carb off that coolant was there. I did not think it was suppose to be. That makes a lot more since now lol. Thanks for dumbing it down for me!

[SubGothius]

Yeah, that can happen if you remove the stock carb without draining some coolant first, which overflows from that coolant port in the carb mounting flange that you'll wanna block with a stainless grub/set screw (M6 or M8, I forget which) sealed with Loctite or hi-temp thread sealant.

[94maxlow]

yeah to show my lack of knowledge on these trucks i had no idea it was a water choke. To say i was shocked when coolant came out is a understatement! I thank you very much for all your information. I am going to start a thread about doing to install. I hope you will come over to it and put your information on there. My hope is that i can take enough photos and document it good enough to help the next person who wants to do a Weber conversion

[zhloea]

Either a DFEV or DGEV Weber 32/36 will work. The DFEV is slightly preferable for easier throttle cable routing with the fuel float bowl placed in front. The DGEV is more readily available and tends to be cheaper, but poses a dilemma of easy cable routing with the float bowl at the rear vs. trickier cable routing with the bowl in front.

Float bowl in the rear makes it run slightly rich braking or going downhill and slightly lean accelerating and going uphill, which is the opposite of what's preferable, but it's not that big a deal. I happen to run a DGEV on my '87 2.6L just fine for the most part, and I just try to brake gently and well in advance whenever possible, though I sometimes stall out on abrupt/panic stops.

The Redline Weber kit K610 includes a DGEV, and their kit K614 includes a DFEV. The latter is necessary if you've got an auto trans, as that allows for a kickdown linkage, but a manual trans can use either one. These kits are available directly from Redline Weber (who seem to be the main US Weber distributor), who also supply them to Pierce Manifolds and Carbs Unlimited (carburetion.net).

If you don't buy new from one of those official Weber/Redline distributors, at least take care to get a genuine Weber made in Spain, not one of the Chinese-made clones offered by EMPI and others. They're "licensed" clones in general design and name/logo only, but they aren't finished to the same exacting tolerances as genuine Webers, so they often can't be tuned to run properly in all conditions. Genuine Webers have a slightly dull/rough looking finish, with the Weber name/logo and "Made in Spain" cast right into the body, and usually have a translucent-off-white electric choke cover. Clones have a bright/smooth finish, with the Weber name/logo only as a decal, tag, or ink stamp, and usually have a black choke cover.

That said, the electric choke cover isn't always a dead giveaway, especially for secondhand carbs, as it's possible to install either choke element on any Weber -- e.g., using the cloned choke element to to upgrade a genuine Weber's original water choke to electric, or using a genuine choke element on a clone to make it look more genuine.

Hi, thanks for the information, I have a 87 manual Montero 2.6, I saw the advantages you said about K614, but seems the K614 is specifically for auto trans, and all ebay seller list this kit specifically for auto trans, so could this kit be used for manual directly or will require some modification? Thanks!

[SubGothius]

The K614 kit with a Weber DFEV will work fine for either auto or manual trans, and is preferable for the reasons I explained above.

The vendors list it for auto trans because that's the only one they make a kickdown linkage for, to shift the auto trans into a lower gear when the pedal is floored.

They list the K610 for manual trans because Weber DGEVs are cheaper and more plentiful, so they prefer to reserve the K614/DFEV for auto trans applications that actually require it.

[zhloea]

The K614 kit with a Weber DFEV will work fine for either auto or manual trans, and is preferable for the reasons I explained above.

The vendors list it for auto trans because that's the only one they make a kickdown linkage for, to shift the auto trans into a lower gear when the pedal is floored.

They list the K610 for manual trans because Weber DGEVs are cheaper and more plentiful, so they prefer to reserve the K614/DFEV for auto trans applications that actually require it.

Thanks for the reply, I currently already purchased a new reman mikuni carb just did not install yet, but I will be really glad to buy a weber because I am a little sick about all the tubes I have to deal with mikuni. So what attract me now is the weber setup looks nice and concise, then how about the overall performance? is the weber k614 better than the mikuni on performance? Thank you.