Mercury V-6, Carburetor Jets

[GT1000000]

Hello to all of the Mercury Outboard Wizards out there...
This is an engine that belongs to friends boat and I have been slowly, but surely trying to revive it...
Serial Number 5875380...
From the info gathered so far here on the forum and elsewhere, the best description I have is that it is a circa 1980-82 V-6 of somewhere between 150-200 HP...
So far, with the help of a close friend and neighbor, who used to work on these engines many years ago, we have had it fired up and set the base timing and the advance timing...
We were unable to get good throttle response from it and after much fiddling, he suggested that we remove and inspect the carburetors...
BINGO!
He nailed it...there are some definite problems with the carbs as I will try to explain as best as possible below...

A break down of what each carb had to offer follows;

TOP CARB...
Used and easy [not] out to remove the Port Main Jet Plug (part#8)...slightly booger-ed up the threads, but was able to run a 3/8 X 24 Tap into it and clean it up...able to remove the main jet (part#10) from the broken end of the plug, totally reusable...
Starboard Main Jet Plug (part#8), not so lucky, tried to get an easy [not] out on it but couldn't get it to bite, had to drill out the Main jet (part #10) and then I was able to get a good enough bite on what was left of the plug and remove it...this side will need a new Plug and jet...
Also removed the float bowl (part #6) to find the starboard float (part #15) was adjusted wrong...

MIDDLE CARB...
Both Main Plugs (part#8) came out with the easy [not] out, both Main jets (part#10) reuseable...
When I removed the Float Bowl (part#6) for further inspection, it had a bunch of loose crud throughout...this has been cleaned out...
The Port float (part#15) was cracked and repaired with some kind of adhesive/epoxy, this will have to be replaced...
The starboard float (part#15) was also out of adjustment...
The Starboard needle (part#13) was flaking the nickle/chrome? from its surface...it will have to be replaced...
* see note below*The Vent Bowl jet (part#2) was completely missing from the starboard side of the carb...will need one of those...

BOTTOM CARB...
No apparent problem with the Main Jet Plugs or Jets (parts#8 & 10)
Port Float needs adjustment...(part#15)
*see note below*Both Bowl Vent jets (part#2) missing...will need both of those...

*NOTE* Now for my question...

How do I determine which Bowl Vent Jets the Mid and Bottom Carbs will need...???
From what I have found online, there are two sizes available...
.096
.084

Almost all of the parts I will need to repair these carbs are available, I am however unable to track down the Float (part#15)...If any one has a good place to hopefully find one of these, please, let me know


Thanks for any help,
GT1M

 

[wired247]

Re: Mercury V-6, Carburetor Jets

Whats the motors serial number?

 

[carholme]

Re: Mercury V-6, Carburetor Jets

From the third line of the first post:

Serial Number 5875380...

Comes up as:

MERCURY - (200 H.P. (1980 ))
Serial No: 05875380 Model No: 1200640

Parts and Service Bulletin list for s/n 05875380:

Search Results - Crowley Marine

Carb Float Mercury 1395-9267 - CP Performance

Gerry

 

[GT1000000]

Re: Mercury V-6, Carburetor Jets

Serial Number 5875380...

Thanks "carholme"!
That takes care of the float...
Any idea on which of these I would need for the bottom carb?

How do I determine which Bowl Vent Jets the Mid and Bottom Carbs will need...???
From what I have found online, there are two sizes available...
.096
.084

I am guessing that I need one for the middle carb, the same as the one that's still there, right?

 

[wired247]

Re: Mercury V-6, Carburetor Jets

OK. Didnt see it there. Whats the series number of the carbs. They are WH carbs but on the side of the flanges there should be a number like 16-1 for the top carbs or 14-1 . It will be a 2 digit number. NOT the casting number. The cast in casting number is worthless. You need the hand stamped series number.

 

[Dukedog]

Re: Mercury V-6, Carburetor Jets

:facepalm: Wh's don't have those on 'em. Look on top flange. Should be a WH ?? (number) stamped somewhere. Might be 20's. If you can find tha WH number I can figure out tha right jetting for your vents. In tha mean time tell us what size tha idle, main jet sizes in each carb. I can use that to determine which WH number ya got if its not on tha carbs......

 

[GT1000000]

Re: Mercury V-6, Carburetor Jets

I only have the Bottom carb on hand...
H-18-3
I will get the number off of the middle one tomorrow and post it...
Thanks!

 

[wired247]

Re: Mercury V-6, Carburetor Jets

They are WH-18's then. The -3 is the bottom carb. -1 would be top. -2 would be middle.

 

[wired247]

Re: Mercury V-6, Carburetor Jets

:facepalm: Wh's don't have those on 'em.

:facepalm: See, I can do that too. WH's do have casting numbers cast into the main body just like the later carbs. They often get referenced as the the part numbers which they are not. Most all carbs of the same model start off with the same casting and then jet machined and jetted for a particular calibration and then get hand stamped for the series.

 

[Faztbullet]

Re: Mercury V-6, Carburetor Jets

You dont need the vent jets as will run just fine without them.....

 

[Dukedog]

Re: Mercury V-6, Carburetor Jets

You dont need the vent jets as will run just fine without them.....

Absolutly, but seems like a guy that won't be happy without em'....................

GT. Need tha jet sizes for mains and idle..............Not just tha wh number.

 

[GT1000000]

Re: Mercury V-6, Carburetor Jets

You dont need the vent jets as will run just fine without them.....

Absolutly, but seems like a guy that won't be happy without em'....................

GT. Need tha jet sizes for mains and idle..............Not just tha wh number.

Well in that case, if the carbs don't need the vent jets, then I would be thrilled not to have to lay out good green to buy them...
Soooo....I guess for the moment, you won't need the jet sizes and we are basically done here...
I'll report back when I get all the pieces/parts needed to repair what is ailing these carbs with an update as to how the engine runs...
Thanks a Ton for all the help, guys!

 

[wired247]

Re: Mercury V-6, Carburetor Jets

If you run without the bowl vent jets you will need to rejet the mains.

 

[Dukedog]

Re: Mercury V-6, Carburetor Jets

No you don't...............

 

[wired247]

Re: Mercury V-6, Carburetor Jets

If you dont mind it running overly rich at WOT after removing the bowl vent jets then yes you will need to re jet. If you like it running overly rich then you do not need to re jet.

 

[Dukedog]

Re: Mercury V-6, Carburetor Jets

That seems ta be a typical thing with you. You have no idea about how to set up a wh carb. Doubt that you have ever ran anything with one on it. No mater what tha theory says it doesn't make a hill a beans as ta where it has 'em or not unless your tryin' ta do some ultra fine tunin' on 'em for reasons other than a fishin' boat. It doesn't increase any more than 1/2 a jet size. Something not even noticeable on a stock motor. Just HOW many of these things have you ran on your so many motors? You build one stinkin' 2.5 and now your tha authority of LITTLE MERCS..........NOT!

Have a nice day.....

 

[wired247]

Re: Mercury V-6, Carburetor Jets

That seems ta be a typical thing with you. You have no idea about how to set up a wh carb. Doubt that you have ever ran anything with one on it. No mater what tha theory says it doesn't make a hill a beans as ta where it has 'em or not unless your tryin' ta do some ultra fine tunin' on 'em for reasons other than a fishin' boat. It doesn't increase any more than 1/2 a jet size. Something not even noticeable on a stock motor. Just HOW many of these things have you ran on your so many motors? You build one stinkin' 2.5 and now your tha authority of LITTLE MERCS..........NOT!



have a nice day.....

Carbs are carbs. WMH, WMV, WH's, carters, walbro, holleys, webers, dellortos...whatever.. Pull the restriction out of the bowl air inlet and the pressure drop across the orifice decreases. Fuel flows out the mains faster. Thats why the bowl air jets are there for part throttle economy. Change that orifice and it does change the dynamics of the fuel pouring out the main jets. You just said so yourself. Normally Mercs are run so pig rich that a little more pig rich won't hurt anything except it uses more fuel.

You dont really want me to have a nice day Duke.

 

[Faztbullet]

Re: Mercury V-6, Carburetor Jets

Carbs are carbs. WMH, WMV, WH's, carters, walbro, holleys, webers, dellortos...whatever.. Pull the restriction out of the bowl air inlet and the pressure drop across the orifice decreases. Fuel flows out the mains faster. Thats why the bowl air jets are there for part throttle economy. Change that orifice and it does change the dynamics of the fuel pouring out the main jets. You just said so yourself. Normally Mercs are run so pig rich that a little more pig rich won't hurt anything except it uses more fuel.

It dont matter on the WH series as on his carbs only 3 barrels use vent jets the other 3 are empty from factory and they are 3,5 & 6..

 

[GT1000000]

Morning Iboats and a very Happy 4th to all...
I have been negligent in my postings due to life being generally in the way, but here goes a bit of a catch up on what has happened since the last update...
After finding all the things wrong with the carbs, I started searching for replacement parts...
Found all the necessary parts but when the dollar signs began adding up, with shipping, we were looking at over 200 bucks...
In comes evil bay...After asking around and finding out that most WH series carbs are interchangeable, I found a complete set, supposedly taken off of a running engine, for 150, delivered...
Upon receiving the brown box from the brown truck, I set to inspecting the package...what I found were 3 very complete and very good looking WH series carbs...
Over time I took each one apart and inspected them for proper float settings, good looking needles and seats, and clear fuel passages throughout...
I then re-assembled them and over the last few days installed them on the engine...
While I was finishing up the installation, I noticed something that had me worried for a bit, but after doing some research, I realized it was a minor issue...I am talking about the difference between the original carbs, which were designed with enrichment ports installed in their float bowls, as opposed to the replacement carbs which did not have this feature, and were designed to work with a choke solenoid and choke plates installed in the attenuator...
I am already tracking down the required attenuator with the choke plates installed, and as soon as I can locate a fair deal, I will install it, along with a choke solenoid...
Another thing I did when installing the carbs is to install a new bulb, in-line fuel filter, and all new ethanol resistant fuel hoses with SS worm clamps...
OK, all that being said, I have been keeping the batteries charged in anticipation of trying out the carbs...
Yesterday evening, I came home from work and got busy trying to start the engine...
The results speak for themselves...
Here is a video of how the engine sounded with the new carbs...

I still have to tweak the idle and timing settings and have a good look at why the engine seemed to be getting hot...but all in all, the engine is running a million times better, throttle response is snappy, the high-for-now idle is smooth and start up is instantaneous...
On another note, if I manually push on the timing advance lever, the portion that connects to the trigger, and manually retard the timing, the idle speed can be brought down to about 800RPM and it will happily idle there with nary a miss...
The next big task, before getting this old tub wet, is to find out why its getting hot [possibly a bad impeller or a stuck thermostat], tweak a couple of wiring issues, and the big ticket item the owner is saving up for...purchasing then installing a new hydraulic steering system, since the current rotary system has failed and the owner of the boat says he is done with replacing cable type steering systems on the boat...apparently this is the third cable type system he has had in this boat and has been convinced that what he has spent over the years on cable type systems, it would be better to invest in a hydraulic system...I agree!
A possible issue that is causing these cable failures has to do with when the boat was "repaired" after sinking, where the person who did the repairs did not bother to route the steering cable correctly and it has always caused binding issues, plus the correct passage to route the cable is currently inaccessible, as it is buried under the the deck...hopefully the hydraulic system will alleviate this problem...
Anyhow, folks...once again, thank you all for the help and support you have afforded me throughout this part of the project and hopefully the next time I pop by, it will be to post a video of a great running engine, getting us to some prime fishing spots...
Till then, Safe and Happy boating to all!