wmv carb conversion on xr6

[diskvalve]

I have just removed the wmh 14s with the 1 inch venturis on my 1992 xr6 and replace them with newer WMV 16s with the 1.312 venturis. I got all the right linkage rods and throttle cam installed and the throttles open perfectly (they are backwards opening compared to the wmh style. The motor runs great with them but I have a minor poblem with the oil pump travel that even the mercury tech did not seem to be able to figure out. According to my service manual I have the mark on my oil pump lever that corresponds to the mark on the block lined up at idle properly but the oil pump lever does not go much past half way as opposed to when I had the older carbs and linkages it opened the lever all the way to the third mark. My service manual only says to align the marks at idle position and makes no mention as to what the full throttle position should be on the oil pump. The mercury tech I spoke with said that the pumps have not changed design and that what I have done should work, but that this carb change is not a common update and mercury has not published any literature about this. My question is whether or not my pump opening just over half way is all that is required ? Also if anyone can tell me if possibly the lever on my oil pump is in fact different than a newer style? If anyone reading this has a newer style(1996- up )carbed merc that the oil pump link arm runs off the center carb could you tell me if the oil pump opens all the way or just past half way. thanks -- mike

[gap1949]

Pump linkage connection inside or outside of black plastic carb linkage? I think you changed from out to in. Makes the travel off. Take the long oil pump linkage and a short pump connector will give you more travel. You will have to bend the long linkage to prevent binding. Most pump linkage connectors I have seen have 2 marks for idle and 1 for full throttle. You may have to find a pump with the shorter one, can`nt remember if you can change it on the pump? Be shure you are getting enough oil. You can add to gas to be safe untill you are shure. Are you will be better off getting more oil at idle on your adjustment, just a thought.

[diskvalve]

According to mercury, the lever on the pumps are all the same with the #200 stamped on them and the link arms for the short newer WMV carbs are also the same. I did fabricate a longer link arm but all it does is changes the end point of the travel and I can,t get the idle line to mark up with the longer arm but it will open up to the wide open line . When I put the link arm that came with the carbs on I get the idle mark to line up but at full throttle I only get about half way between the second and third marks. It is as if I am missing about 1/4 inch of travel. I called a merc dealer 100 miles away that has a 2002 carbed xr6 and had him check how far the oil pump opens and he said it only opens half way as well. Can anyone confirm this and possibly explain why . -- mike

[diskvalve]

Gary, thanks for your reply. The brass knob on the plastic piece on the carb cantilever is in fact pointing inward. I can see that if it was on the outside it would give me a bit more travel. Is that brass knob threaded into the plastic or molded in ? I would like to reverse it but I am afraid of snapping something. The way it is now I have extended the link arm on the threads as long as I dare and I am still around 3/4 open according to the three marks. I think I will run 100:1 premix in conjunction with my injector pump until I can confirm I am getting enough oil. By the way these WMV carbs start and idle like an optimax and definately improve my idle quality lots. I think this is a reasonable upgrade as the old wmh carbs were hard starting and rough idling. I think mercury should have explored this upgrade.I have a 1992 xr6 with bridgeport tuner ,eagle one alien cowl, rubber 4 petal cage boyesen reeds , intake port matched to the reed cages with a 1/2 in cross drilled hole joining each intake tract, and ex port roofs raised to match the block. I had wmh 39s in it with .066 mains on top carb and .064 on the rest but they idled bad and were hard starting and would bog out occasionally . I was getting 69.2 mph on my gps at 6000 rpm with a 25 tempest on an astro 18dcx. --- mike

[Superdave]

just remove the oil injection? It's only a matter of time. If you turn over 6,000 rpm's much the drive gear will eventually strip and BLOOEY!
Dave

[diskvalve]

I may remove the oil injection if I can,t confirm I am getting enough oil. I contacted mercury tech line and he is going to find out for sure if the newer motors only open the pump 3/4 of the travel. --- mike