Mercury wmv carbs

[Merc25jo]

I know this has been discussed before but I have the wmv 16 carbs on my engine (2003 mercury xr6) and I found a good deal on the wmv 18's from a 200 hp. Will it make a noticeable difference of any kind? Is the jetting the only difference? There's got to be a reason why the 18's are 150$ more than the 16's if you buy them new. Will they help at all?

 

[Dukedog]

Re: Mercury wmv carbs

Will it make a noticeable difference of any kind?

No. Jets are tha difference. Cost, 'cause its for a 200..

Very little you can do to yours. Its an "electronic", O-ring head motor. Some might "suggest" something for it but it ain't gonna happen with what ya got unless ya make some major changes..........

 

[Faztbullet]

Re: Mercury wmv carbs

As Duke posted...casting is same ,only differece are emulsion tubes and jetting only thing that will happen is it will run richer...

 

[wired247]

Re: Mercury wmv carbs

All the WMV's are big venturi carbs. Making it run richer with fatter jetting like the 200's use to compensate for their porting won't do you any good. What will do you good is to have the heads milled a bit tighter to bump the compression up. Yes, O ring heads can be milled and have the O ring groove re cut. Several shops will do it but its not as cheap as cutting gasket heads. Then you may need to slightly re jet the carbs and you will need to run premium gas.

 

[Merc25jo]

Re: Mercury wmv carbs

Glad I didn't make that mistake, I will save my money. Still love my xr6! Thanks guys!

 

[Merc25jo]

Re: Mercury wmv carbs

Yes that is my plan I've heard that was best mod you can do to the newer xr6. The rev limiter really holds it back.

 

[Merc25jo]

Re: Mercury wmv carbs

I have the Boyeson reeds installed which I think helped idle and whole a lot. Also have Bobs 200 tuner, don't think I gained much but I think it sounds better. For a 150 it has a heck of a hole shot. I am dying to get the heads cut.

 

[Dukedog]

Re: Mercury wmv carbs

I have the Boyeson reeds installed which I think helped idle and whole a lot. Also have Bobs 200 tuner, don't think I gained much but I think it sounds better. For a 150 it has a heck of a hole shot. I am dying to get the heads cut.

If ya do tha heads do some research. Not but a coupla folks that do tha factory O-ring stuff "right" cause it has ta have tha "spaghetti" grove cut also. I would look at Diamond or JSRE. Probably around 400+ bucks........It might give ya a little more bottom and mid grunt but don't expect any more than that. If ya don't put a bunch of comp and able ta really turn tha wick up (RPM) on one it might be kinda disappointing..............jmo

 

[sam am I]

Re: Mercury wmv carbs

I'm pretty sure you'd have to up oil flow as well if ya do a/any 135-175 to 200/225 fatter WMV re-jetting's(among the few other things), and this makes sense (right?), you have to increase oil volume if you increase jet size....e.g., if the carb jet bores the oil/fuel is flowing though is increased, then flow volumes increases, if flow volume increases in carb, then flow volumes of the oil pump need to increase relatively as well to supply/keep up with the increased demand presented via the new bigger carb jets.

This from merc manual....

"1992 and Newer
Model 105/140Jet/135/150/XR6/MAGIII/175/200/150XRI/175XRI/200XRI
PRO MAX/SUPER MAGNUM 150/200/225

Two different capacity oil pumps are utilized on V-6
outboards.

Flow specifications are as follows:

135 thru 175 Models including Pro Max/Super
Magnum Model 150:

@ 1500 RPM with oil pump link arm ATTACHED =
6.8cc ? 10% in 3 MINUTES

@ 1500 RPM with oil pump link arm DISCONNECTED
=17cc ? 10%in 3 minutes


200 Model including 200/225 Pro Max/Super Magnum
Models:

@ 1500 RPM with oil pump link arm ATTACHED
=8.2cc ? 10% in 3 MINUTES

@ 1500 RPM with oil pump link arm DISCONNECTED
=19.2cc ? 10% in 3 minutes"

 

[Faztbullet]

Re: Mercury wmv carbs

I'm pretty sure you'd have to up oil flow as well if ya do a/any 135-175 to 200/225 fatter WMV re-jetting's(among the few other things), and this makes sense (right?)

A 150s a 150....

you have to increase oil volume if you increase jet size.

Nope as jet has nothing to do with oil mixture its 50/1 thru a .052 jet and 50/1 thru a .068 jet.

if the carb jet bores the oil/fuel is flowing though is increased, then flow volumes increases, if flow volume increases in carb, then flow volumes of the oil pump need to increase relatively as well to supply/keep up with the increased demand presented via the new bigger carb jets.

The carbs share the same castings and will flow the same CFMs but the 150 has a different port map and rpm range,emulsion tubes (which mix the air/fuel from jet together) and only way any volume can increase is increase in rpm's, which oil pump puts out 50/1 at WOT no matter what the increase, it just gets spun faster. The reason 200 has different pump is porting,rpm range,different cc head and factory likes em a little richer . This is some of the reasons why you cant bolt on a set of 200 carbs and make it a 200 as air/fuel ratio will be off (pesky emulsion tube) and will need to be rejetted smaller as it will be rich. Now if you do head cutting /advance module float test the oiler will need to get gone so it wont need pump upgrade

 

[Dukedog]

Re: Mercury wmv carbs

Don't mater anyway. With what your thinkin' 'bout doin' ya won't need ta change a thing. Merc jets their "production" carb and ecu stuff fat ta start with. Not much but they do. They aren't gonna turn Joe Blow Public loose with a "lean burn" motor.........I run some of my motors with as much as 165 lbs and STOCK jettin' in WH's. Its pretty much a perfect burn. Tha only thing ya really need ta do is "BE ABLE TA READ THA PISTON TOPS" after ya do anything to your motor that has ta do with fuel delivery. So I wouldn't worry 'bout a thing with or without tha oiler.........jmo

JAN. I'm a firm believer in leavin' a very good stock "cdm" motor alone. Tha 'lectronics are very restrictive on its perimeters. Its not gonna make a hill a beans difference ta 99% when messin' with it. Most end up in tha bone pile 'cause most are really unknowing of what ta look for "after" things go south.........It can make a difference in a nice long season or a BAD very long season.......... again jmo.

 

[sam am I]

Re: Mercury wmv carbs

A 150s a 150....

I was just speaking in general terms of re-jetting into a 200/225 from....xxx

Nope as jet has nothing to do with oil mixture its 50/1 thru a .052 jet and 50/1 thru a .068 jet.

Are you sure? We're both talking the creation point w the oil pump system, right? Not pre-mixing?.......With pump, the mixing point if you will, is the "Tee" and is where the fuel oil mix begins and jett settings is a direct relation of why the mix resides..

The oil is of course being metered/pumped at a given volume at a given rpm dictated by the position of the oil injection arm , if running at some chosen rpm, say 5000 RPM and requiring 50:1.... Having larger jets installed and running at same RPM, same arm position, then the volume of mix through the jets has had to of increased (fixed vacuum through larger diameter bore in jet), say 105% for example just to grab some number. Seems to me, the oil pump volume would have to increase this same 105% else there's a deficiency in oil and the mix would lean out (recall there's fixed oil metering with mixing w gas at Tee).......Thus at some point, merc manual indicates 135-175 to 200/225 is where they increase oil volumes, i don't now why exactly just at this point but, i guess this point was where they did recognized a large enough deficiency would be an issue and they increased oil flows volume.......that is JMO though.

 

[wired247]

Re: Mercury wmv carbs

The oil metering is independent of the carburetors except for the common reliance on the throttle arm. Basically the pump has two settings. Idle and run. If its at idle it meters less oil into the system. If it is at run it meters 50:1. There is no stepped progression. Its just a little or a lot. The carburetor jets have absolutely nothing to do with it. The major drawback to the system is that if you are putting around at idle and suddenly gun it you have a few seconds of light mix oil going through the system under full load.

 

[Faztbullet]

Re: Mercury wmv carbs

It really dont matter as the Xr6 has the 200 oil pump on it anyway....

 

[sam am I]

Re: Mercury wmv carbs

The oil metering is independent of the carburetors except for the common reliance on the throttle arm. Basically the pump has two settings. Idle and run. If its at idle it meters less oil into the system. If it is at run it meters 50:1. There is no stepped progression. Its just a little or a lot.

I'm wondering about that, i'm not at home(back in Portland right now, i can't go take it apart)..........I'm thinking though there is a linear progression to this pump based on the arm position. I could be wrong though.....

The carburetor jets have absolutely nothing to do with it.

With what? Why merc increased oil volumes when running bigger jets in 200/225? If so, i disagree...

I will try it this way.........

1500RPM's = 17cc/3secs or 5.66cc/sec is (using one of several spec's I/merc listed above, any would do, i just grabbed one) the factory spec’s fixed output of the oil pump based on the arm position at this RPM, correct?

In order to have a mix of 100:1 (we'll assume 100:1 @ 1500RPM's is reasonable) then 5.66*100 = 566.66cc of gas must mix with 5.66cc of oil to achieve 100:1, So far so good?

Therefore, the engine at 1500RPM's must use/burn/consume approx. 566.66cc of gas/sec because the pump is set/fixed/pumping/metering 5.66cc/sec, the pump arm says so, it hasn't moved, good so far?

Now, pop in a new fuel/mixture jet with a bigger bore, and of course with ALL the above the same.

Crank up the engine, set it back to 1500RPM's, would you guess with a bigger bored jet, the mixtures' volume will increase or decrease?

I say increase....lets guess it consuming 600cc's/sec of mix, that's certainly reasonable? (Up from 566 + 5.66 = 571).....bigger bore jet, same RPM = more volume, good so far?

BUT.......the oil pumps' output has a set/fixed volume still here right? The arm is in same position, right? Same RPM, right? Therefore 5.66cc/sec of oil is all we're get'n, no more, no less.

Little math......

600 - 5.66 = 594

594/5.66 = 105

105:1 = leaner

But I require/desire 100:1 with my newly bigger bore jetted carb 200/225hp engine @ this same RPM, I’d have to increase? Yes, oil volume to richen it up. This is indicated by the manuals spec's

The major drawback to the system is that if you are putting around at idle and suddenly gun it you have a few seconds of light mix oil going through the system under full load.

I agree this occurs

 

[sam am I]

Re: Mercury wmv carbs

It really dont matter as the Xr6 has the 200 oil pump on it anyway....

That would be true, total moot point if this is the case.

 

[wired247]

Re: Mercury wmv carbs

The oil pump has 3 states. Two of them are run states. One is idle and one is the high speed circuit, basically anything that isnt idle. The other state is the failure state. Thats the high oil state where if the pump fails it is wide open oiling. The carb jets on the 200 are bigger to provide a richer charge both in oil and in fuel at the higher RPM's that the 200 is designed to run at with its larger and higher porting. The last thing you want at 6500 RPM is a lean condition and Mercury really likes to avoid warranty costs even if it means increased oil and fuel consumption far in excess of what it would normally take to produce 200 HP.

 

[Faztbullet]

Re: Mercury wmv carbs

Crank up the engine, set it back to 1500RPM's, would you guess with a bigger bored jet, the mixtures' volume will increase or decrease?

I say increase....lets guess it consuming 600cc's/sec of mix, that's certainly reasonable? (Up from 566 + 5.66 = 571).....bigger bore jet, same RPM = more volume, good so far?
BUT.......the oil pumps' output has a set/fixed volume still here right? The arm is in same position, right? Same RPM, right? Therefore 5.66cc/sec of oil is all we're get'n, no more, no less.

If it was mixing 50/1 before the jet change it will be 50/1 after the change as jets have NOTHING to do with oil mixture or ratio as its mixed BEFORE the carb. Forget the math , the oil pump,arm settings, if you run premix at 50/1 and pop in a .a .030 bigger jet it will flow more but its still flowing 50/1. Here something for you to think about also, if you rebuilt your engine and bored it .030 over and added bigger jets for the increased CC displacement and it was a 200/225, you be chit out of luck as there isn't a bigger oil pump using your theory..