Replacing a Mikuni Carburetor with a Weber Carburetor

[BJH324JH]

What do I need to do to replace the Mikuni carburetor to a Weber carburetor? I have a 1988 Mitsubishi Mighty Max 2.6l 4x4 manual transmission pick up truck.

UPDATE: 11:48 A.M. 6/16/2019 Sunday
I purchased the Weber 32/26 DGEV K610 carburetor from Carbs Unlimited and received it a few days later. Although, the carburetor has DGAV stamped on the base instead of what I believe is supposed to be DGEV. Anyone know why that is? I took multiple pictures of what you will get when you order the Weber 32/36 DGEV K610 carburetor.

I received this box that was in another box(inception :
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Overall contents of package:
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Contents laid out on table:
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Pictures taken of the carburetor body:
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UPDATE: 11:18 P.M. 8/11/2019 Sunday
The following pictures are the components you will receive with the k610 conversion kit. I took a picture of each component to show a closer view.

IMG_5061.jpg IMG_5063.jpgIMG_5064.jpgIMG_5073.jpgIMG_5089.jpgIMG_5095.jpgIMG_5097.jpgIMG_5099.jpgIMG_5100.jpgIMG_5102.jpgIMG_5103.jpgIMG_5105.jpgIMG_5112.jpgIMG_5115.jpgIMG_5116.jpgIMG_5122.jpgIMG_5125.jpgIMG_5126.jpgIMG_5127.jpgIMG_5128.jpgIMG_5134.jpgIMG_5130.jpgIMG_5132.jpgIMG_5133.jpgIMG_5137.jpg

The first three pictures were taken before the conversion started:
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These next pictures, I started removing...
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Carburetor removed with it's annoying vacuum hoses:
IMG_9923.jpg

Helpful Links:
Where I ordered the Weber 32/36 DGEV K610 Carburetor:
http://www.carburetion.com/Products/ProductDetails.aspx?Part=K610

Weber 32/36 DGEV K610 Carburetor Diagram:
http://www.carburetion.com/diags/3236DGAVDiaginfo.asp

Identifying a Fake Weber Carburetor:
http://genuineweber.blogspot.com/

Redline Weber Contact Information:
http://www.redlineweber.com/contactus.html

What DGAV, DGEV, etc... means:
https://motofaction.org/mechanical-1...l-differences/

[geezer101]

You'll need a K610 adapter kit and then decide what model Weber - either the 32/36 DGEV or the 38/38 DGES. There are intake manifold modifications you will also need to factor in (sealing the coolant port under the carb seat gasket and the coolant barb that normally runs to the Mikuni water choke). Delete the mechanical fuel pump on the head and install an electric pump by the fuel tank (a high volume/low pressure pump - check ebay, but I'd look at the Carbole 42S as it's good value for money and quieter than the Carter P4070 + more compact)

[BJH324JH]

You'll need a K610 adapter kit and then decide what model Weber - either the 32/36 DGEV or the 38/38 DGES. There are intake manifold modifications you will also need to factor in (sealing the coolant port under the carb seat gasket and the coolant barb that normally runs to the Mikuni water choke). Delete the mechanical fuel pump on the head and install an electric pump by the fuel tank (a high volume/low pressure pump - check ebay, but I'd look at the Carbole 42S as it's good value for money and quieter than the Carter P4070 + more compact)

Firstly, I want to thank you geezer for the help once again. You are much appreciated.

Second, what would be the difference between the Weber 32/36 DGEV or the 38/38 DGES? What would be the optimal choice for my vehicle?

[geezer101]

They are both 'good' - the 32/36 will be a big step up in both fuel economy and overall performance once you have it dialled in, but the 38 DGES will give you more top end and will be the option if you are planning on building a street engine. The 38 is a more modern designed carb and from what members have been saying it seems to be the carb Redline and other genuine product vendors have more of a tendency to recommend now.

[pennyman1]

FYI - the adaptor kit for the 38dges is different that the one for the 32/36 dges / dfav carbs - the 32/36 top plate is tapered for the 2 different barrels , vs the 38 is the same size on both ends.

[BJH324JH]

I think I'll be getting the 32/36 Weber because it seems that's the carburetor that most members here on the website convert to. I also have been doing a bit of research on these carburetors and unfortunately there is fakes floating around. Who sells genuine Weber carburetors? Now for the installation, what should I look forward to? What should I do to prepare the truck for conversion? Thank you guys for being patient with my questions.

[SubGothius]

Redline seems to be the main official Weber distributor in the US; others like Pierce Manifolds and Carbs Unlimited apparently resell Webers and related parts from Redline, though they may also sell an "economy" carb option that would be a clone to avoid. Main thing to look for is the Weber name, W logo, and "Made in Spain" cast into the body (not just a sticker) and the white/translucent electric choke-spring cover (clones have black choke covers, though I've seen secondhand apparently-genuine Webers retrofitted with black-covered clone electric chokes, e.g. if converted from a water choke). BTW, there's an eBay seller "userid[somelongnumber]" who may just be Pierce Manifolds; at least, I bought a linkage kit from them that wound up shipped by Pierce.

[geezer101]

Read this - http://www.mightyram50.net/vbulletin...carb-Becareful!!!!!!!!!!!!

[BJH324JH]

Is this the correct one for my truck?
https://www.ebay.com/itm/1979-1989-M...IAAOSw7UZbMxnj
Seems to have everything ready for conversion.

[geezer101]

Yep it's a winner. Someone gave a review based on their efforts of installing it. That kit + an electric pump similar or the same as the one I recommended in my above post and you're almost ready to go. You'll need a fuel pump block off plate for the mechanical pump delete and spend a bit of time experimenting with the ignition tune to get it running nicely. The only thing I'm not super happy with is the open element air cleaner. It'll work, but getting a cool air charge from outside of the engine bay will optimise performance.

[BJH324JH]

Yep it's a winner. Someone gave a review based on their efforts of installing it. That kit + an electric pump similar or the same as the one I recommended in my above post and you're almost ready to go. You'll need a fuel pump block off plate for the mechanical pump delete and spend a bit of time experimenting with the ignition tune to get it running nicely. The only thing I'm not super happy with is the open element air cleaner. It'll work, but getting a cool air charge from outside of the engine bay will optimise performance.

Okay, I'll see if I can make a fuel pump cover out of aluminum for the cylinder head. As for the pump, I'll look into the one you stated before. What is the ignition tune? Is there examples of cool air charge you are talking about?

[geezer101]

*I haven't looked for this on any of the tips/threads but there is bound to be pics and info from a member. Anyone got a link?

[geezer101]

The Weber is a vacuum beast - it will generate more vacuum than necessary to operate the vacuum advance on the distributor and as a result, will cause over advance. You'll have to play with the distributor in order to find a point where the engine won't experience pinging/knocking under acceleration.

As for the air cleaner, you can take a stock air cleaner box, cut the centre out of it where it mounted onto the Mikuni and make an adapter plate to suit the top of the Weber. You may need a spacer to lift the air cleaner up from the carb depending on if it fouls on anything. This sounds hard but all you need to really do is make a hole in a piece of cardboard that fits around the intake on the top of the carb (trace the hole from the top gasket in the kit), cut a round hole in the bottom of the air cleaner box, sit it on top of the carb where the mounting studs normally hold it in place, trace the hole onto the cardboard and use the cardboard as the template for your adapter (4mm thick alloy plate would be ok) and make some alignment marks so you don't goof when you put it together. The hardest part of this is making a bracket where the air cleaner cover can bolt down onto it as you won't have the stud like what's on the Mikuni to bolt it down. There is an adapter made for this job off the shelf if I recall.

Cut the alloy plate and drill some holes through the air cleaner base into the adapter plate. A bead of silicon and some rivets - done! Looks stock and has the cold air charge from the factory ducting (if you lengthen it and direct it out of the engine bay it will add torque)

[85Ram50]

I did the mod on the OE air cleaner box and posted about it on here. I also posted some pics and comments about putting in a new Weber. IDK if that will help I just signed in to say there is an adapter for the airbox to Weber mount which will save you lots of aggravation. It is not as easy as Geez thinks. The OE hole for the Mikuni is a cone tapered down an inch or so, that you have to make cuts and hammer flat before cutting the hole then you will have to figure out how to make it airtight. I used a bunch of cork to fill the gap where the adapter will go and coated the cork in red gasket sealer. If I'd have known about the adapter that is what I would have done.

Found a couple adapters https://www.ebay.com/itm/LC-Engineer...MAAOSwQYZWxj6R https://www.ebay.com/itm/WEBER-32-36-DGV-AIR-FILTER-ADAPTER-TO-5-1-4-AIR-CLEANER-WEBER-38-38-NEW/272527062295?hash=item3f73e0f517:g:AIoAAOSwblZZJHk R

[geezer101]

Got a feeling this is the one - https://www.ebay.com/itm/SUZUKI-SAMU...kAAOSwzaJX7Yjb

[85Ram50]

Got a feeling this is the one - https://www.ebay.com/itm/SUZUKI-SAMU...kAAOSwzaJX7Yjb

I see how it would mount to the carb. I do not see how the air cleaner would be attached to it. I can infer that long bolt might be meant for the center hole to hold the top down, and by that the whole housing, Is that the case?

[pennyman1]

That is the one to use - also listed for a Toyota air cleaner...

[85Ram50]

FF just crashed while I was uploading pics!
OK I put in a new spacer so I took pics while I had it off. You can see I used the base plate from that joke square air cleaner as a washer. I had to get longer hex bolts. You can see the cork I coated in gasket sealer. I got some squares of cork at Joanne Fabrics. It was one package. I also used JB Weld to seal the cuts I had to make to get it to hammer flat. Ditto the hole in the top for the post.
lookc.jpg lookc2.jpg lookc3.jpg
Oh yea I had to put a hex bolt into that hole on the left in pic 1. Sorry do not remember the size.

[BJH324JH]

I called the Weber contact support to make sure the k610 was the proper kit for my truck. He confirmed it was. While I was on the phone with him, I took the opportunity to ask him some technical questions. My first question I asked him was if I needed an electric gas pump. He said no and that the mechanical fuel pump was good. I just need a regulator. He said the Weber only requires 2 1/2 to 3 1/2 psi. Second question was about the air filter housing. He said he never got a complaint about the rectangular styled air filter. Do you guys agree with the Weber contact support guy? If not can you please explain why?

[geezer101]

#1 - Putting a pressure regulator on the mechanical fuel pump beats the crap out of them and can lead to pump failure. Some guys have got away with it but most will opt for deleting the mechanical pump and installing an electric unit. Added bonus is being able to either fit a safety cut off switch or concealing a disable switch so if some A-hole steals your truck, it won't run for long.

#2 - open air filters. Bad. Pulling hot air into an air intake robs an engine of torque and impacts fuel economy (not just these trucks but any combustion engine). The exceptionally short air intake created by a direct mounted air filter is awesome for throttle response but again impacts on low down engine torque. The car manufacturers use a specific volume air intake design and length as a compromise for a high volume production vehicle (middle of the road torque, throttle response and fuel economy). Ever noticed that the vast majority of old school engine have literally the same design air cleaner assemblies?

The Weber is a big jump over the Mikuni 32/35 DIDTA style carb. You'll notice the difference straight away once you have it adjusted and tuned. The open element filter bolted to it won't appear to 'nerf' performance until you build a ducted intake and run it on a hot day. It will also shut up the intake hiss you'll get constantly as well. It's novel for a while but there will be a point where it'll drive you bananas...

[BJH324JH]

#1 - Putting a pressure regulator on the mechanical fuel pump beats the crap out of them and can lead to pump failure. Some guys have got away with it but most will opt for deleting the mechanical pump and installing an electric unit. Added bonus is being able to either fit a safety cut off switch or concealing a disable switch so if some A-hole steals your truck, it won't run for long.

#2 - open air filters. Bad. Pulling hot air into an air intake robs an engine of torque and impacts fuel economy (not just these trucks but any combustion engine). The exceptionally short air intake created by a direct mounted air filter is awesome for throttle response but again impacts on low down engine torque. The car manufacturers use a specific volume air intake design and length as a compromise for a high volume production vehicle (middle of the road torque, throttle response and fuel economy). Ever noticed that the vast majority of old school engine have literally the same design air cleaner assemblies?

The Weber is a big jump over the Mikuni 32/35 DIDTA style carb. You'll notice the difference straight away once you have it adjusted and tuned. The open element filter bolted to it won't appear to 'nerf' performance until you build a ducted intake and run it on a hot day. It will also shut up the intake hiss you'll get constantly as well. It's novel for a while but there will be a point where it'll drive you bananas...

Excellent reply. I will go with your suggestions. Should I take into consideration the fuel filter? Like do I keep the old system or get a new system? Also I don't feel comfortable with a plastic fuel pump. Is there a metal alternative?

[geezer101]

And for one of the great mysteries you made an inquiry about - the DGAV vs DGEV. The 'A' refers to 'aqua' (water choke) and the 'E' is electric. This particular carb is one of the times where the part designation makes sense - 'D' dual, 'G' gradual/progressive throttle, 'E/A' choke designation electric/water but the V is a bit ambiguous (might be throttle linkage orientation as there are a few different throttle layouts)

[geezer101]

The stock fuel filters work fine. The drop in fuel pressure passing through it won't affect anything but you'll need a filter before the pump to protect it from any debris that could be picked up straight from the tank (the pump should be mounted as close to the fuel tank as possible) As far as I know there aren't any plastic fuel pump assemblies but the mechanisms will have some kind of plastic casing (reduces corrosion risks and impact damage etc). You can use the Carter P0407 (I am not a fan of these 'rotary' style pumps - they're expensive, noisy and I had one fail spectacularly which ended up clogging a fuel filter with brass) or something like the Carbole 42S pump I've recommended from ebay on a number of different posts. Same pump as the Mr Gasket 42S but a third of the price (same pump right down to the part # on the pump housing/body)

[BJH324JH]

The stock fuel filters work fine. The drop in fuel pressure passing through it won't affect anything but you'll need a filter before the pump to protect it from any debris that could be picked up straight from the tank (the pump should be mounted as close to the fuel tank as possible) As far as I know there aren't any plastic fuel pump assemblies but the mechanisms will have some kind of plastic casing (reduces corrosion risks and impact damage etc). You can use the Carter P0407 (I am not a fan of these 'rotary' style pumps - they're expensive, noisy and I had one fail spectacularly which ended up clogging a fuel filter with brass) or something like the Carbole 42S pump I've recommended from ebay on a number of different posts. Same pump as the Mr Gasket 42S but a third of the price (same pump right down to the part # on the pump housing/body)

I am a bit hesitant about buying the carbole 42s as that has mixed reviews. It seems like you have to get lucky to get a good one.

[geezer101]

I am a bit hesitant about buying the carbole 42s as that has mixed reviews. It seems like you have to get lucky to get a good one.

Yeah, I've noticed they are hit and miss. But then you don't know how the people who've bought them have installed them and not everyone is either going to know or admit they screwed up mounting them.