Link & Sync Throttle Cam question,1990 Merc v-200 2.4L

[danamul1977]

Can someone tell me where the Roller Arm should be placed adjacent to the two marks on the Throttle Cam above casting # 95790. The merc manual has me doing this with a 1/8" rod perpendicular to the carburetor adaptor flange, but that puts the roller way below the two marks, and I am having major bogging down issues. So I read somewhere that the roller arm should be in the middle of one of these marks, was going to try that, but I don't know what mark the lower or upper mark (see picture) I think its prob the lower mark? ty would like to figure this out.

 

[Dukedog]

long mark to center of roller.. might need ta loosen carb linkage screws (all three) and/or move "barrel nuts" on either end of tha rod ta get it where it needs ta be.. jus be sure there is a tiny "gap" between roller and cam when done... doubt thats gonna be answer to "bog" problem..... that could be several things...

 

[danamul1977]

What is the point to the Tiny gap?

Prob not, I just ordered a stator not sure if that is it. I was just thinking that the timing advances way before any of the carb's really open, if i just step on it, thats the only way i can get on plain. If i tried to move the throttle up gradually it would prob die. Gunning it, it tries to die, but then I think the carbs open enough and it shoots like a rocket, but only gets to 4200 rpms and is timed at 24-25* btdc.. Prob to high btdc? but it is running without the spark advance box, so idk where to really put that.

 

[danamul1977]

No Title

That book with the stator I have stamped on the stator does not have the WH46 carbs in it. The carbs go from wh1-wh29 in this book with the 16 amp stators. My other book with the 40 amp stators have carbs from wh34-wh49. This motor was used for racing in the early 90's and had three holes cut into the exhaust housing (picture), that they have patched up now. The wh46 carbs i have were over jeted quite a bit, I was thinking to compensate for this increase in air flow. What im wondering is if they could of put larger carbs on this that worked when It had the holes open in the exhaust, but they should be something more like wh28 carbs. Hard to know if I don't have a S/N that is correct. Or wonder if I should put a 40 amp stator on it with the wh46 carbs.

U can see how off the mark the roller is on those marks.

 

[Dukedog]

46's are justa a better performing carb than some.. i liked 'em better than tha 20's or 22's... they were also a stock production carb on tha 200's and some of tha high performance 2.4's.. those holes in tha down housin' tells me tha guy was a hack so no tellin' whats up with it..... goin' to a 40 would take a few $$.. flywheel, stator, 2 regulator/rectifiers...

timing starts as soon as ya push tha gas petal.. tha gap allows tha timin' ta be a touch ahead of throttle plates.. i have had as much as 3/8" gap on tha hot rods....

 

[danamul1977]

Im not understanding what that 3/8" gap is? Is that the clearance between between roller and throttle cam at w.o.t., or is that the distance between the Dia. Rod and the carburetor adaptor flange? How do i measure that gap?

one of the high speed jets was a .98 so, rest .88,.86,.86,.84,.84,.84, I bought the stock jets to test.. I dont have any regulators just a rectifier. No advance module or lubalert (whatever that is)

going to hook the gas straight to it, and take off the attwood connectors, the male one is plastic maybe its a low fuel problem, as to why i cant get it over 4200 rpms.

compression is 122 on top 4 and 112 on bottom two, tested coils and spark wires. trigger tested good on all wires.

 

[danamul1977]

I think you mean between the roller arm and throttle cam, wow that's slot of gap if it's what I think you mean. That thing would just rev and gun then..

 

[Dukedog]

I think you mean between the roller arm and throttle cam, wow that's slot of gap if it's what I think you mean. That thing would just rev and gun then..

yeah, gap is at idle.... doesn't need ta be that big. jus a little clearance is fine... probably had some small cc heads on it at one time (one reason for jet changes).. yeah go straight to fuel pump...one check for fuel delivery is pumping tha bulb when is actin' stupid.. if it straightens up then look at bulb, pump and/or carbs need attention....

 

[danamul1977]

Took the carb apart today and set all of the floats from the base of the carb 1/16" to the absolute bottom of the floats not that curved up area.. I think that's how you do it? I did not change the nettles, they didn't look pitted, is there a way to know if one of them is not working properly? Checked compression with fuel in the carbs 140 top 4, 124 bottom 2, I'm hoping that's OK, not sure why the bottom ones are both lower.

 

[Dukedog]

set floats by holdin' bowl upside down.. floats should hang level when bowl is held level.. needles very seldom go bad.. one thing with tha wh carbs is tha gaskets.. all of 'em, they need ta be new any time ya take it apart re-assy... no mater what tha gaskets look like.. will save ya from chasin' your tail down tha line..

 

[danamul1977]

No Title

Thx a lot Duke for all your help so far, I have one more syncing question with pictures that does not make sense to me.

I have it timed from 8*atdc to 24* btdc and have that boging down issue, untill the carburetor butterflies open then it goes, but still not past 4200rpms, question is.

The timing advances from 8*atdc to 24*btdc without the carb butterflies barely opening, Can this be right? The way that throttle cam works it seems like thats how they have it set up, but shouldn't the timing advance in unison with the butterflies opening? seems like it just revs up and doesn't move the boat untill the butterflies open, then takes off. The only way I could make them open in unison is to set that roller way higher on the throttle cam. I dont know...

 

[Dukedog]

first pic is right if tha butterflies are fully closed... it supposed to advance ahead of tha butterflies.. two different arms (bottom half throttle, top half advance) with tha big spring in tha middle where they join... with throttle fully depressed both throttle arm and advance should be against they're appropriate stops.. throttle stop is 1/4" bolt towards "front".. advance is 1/4" bolt above on tha "block" half and butterflies should be "flat", open.. if its doin' all that and only turnin' 4200 ya gotta another problem

 

[danamul1977]

Ok, well the top half is fully advanced and the butterflies are just barely open, then the bottom half opens the butterflies with it already being fully advanced, seems weard to me, but I'm taking it out again after I get the new stator.

 

[danamul1977]

Ran it yesterday, and I think its fixed. Was either the stator or fuel bayonet. I put on a laser II 25p and it ran at 4600rpms with the motor tilted down, got it to 5200 trimming it up. Its on a 1983 ranger v375 17' 10" boat I would think it could push this faster, so question is, I'm running this at about 23.5 max btdc timing without the advance timing module. Should I push it to 25-26 or is that to much. It is supposed to run at 26* but changes from 20* to 26* after 5400rpms with that advanced box, just looking for your thoughts on this? Appreciate all your help on this Duke, you helped me get this running alot better then it ever has.

 

[Dukedog]

22 ta 23* is jus fine.. any thing over 22 you will never see any difference with your boat... motor needs ta go 5800 ta 6 grand wfo throttle... 5200 ain't enough... a45 tempest or trophy may help if you can get tha rpm up... go here ta get "base startin' motor height".. really need a water pressure gauge to get dead on with height, offset and prop combination...

http://www.stevescustomprops.com/faq...engine_height_