New Carbs fit?

[varg24]

Hello all, I have a quick question that I would like to post. I picked up a pair of carburetors to replace my one set that has tons of issues. The set that I picked up were from a 1997 800XP I think, and I am replacing a set on my 1999 Challenger 1800. Both sets are for the 787, and both sets have the acc. pump.. There are some minor differences between the two, such as the fuel pump, the choke plate has an extra hole, and the nozzle for the accelerator pump is offset versus right in the middle of the carb.

Does anyone know if there is any major issues concerning swapping these two sets out? My current set of carbs has major issues such as the acc pump not working, and the brass nipples for the fuel delivery broke, and lastly, the high speed adjust is rusted and broke off in the body. I really need to know if the set I bought will replace it.

Thanks for any help

 

[Dr Honda]

Just make sure that the jeting is right for your boat... and you will be fine. Since they came off an 800... they are going to be very close, if not exact.

 

[varg24]

Thats good news.

I am hoping I can eliminate the fuel pump that is on the new ones I bought, and just replace with the cover from my original set of carbs. (my fuel pump is external). Should I also swap the valves with my old set. I see that there are numbers stamped on them and they are a bit different.

I will definately check the jets and also the pop off. Is there anything else I should pay special attention to?

 

[Dr Honda]

What valve are you talking about? The needle and seat?

If yes... then yes. BUT... make sure the pop-off is right.

 

[varg24]

Actually, I was talking about the butterfly valves. They have a stamped number on them. Not sure if it was a reference or not. Also, the choke butterfly valve has 2 holes in it versus my original that has only 1 hole in it.

 

[Dr Honda]

NO... don't change them. The number is probably the size, and that was fit to the carbs. Just because they are "40mm" doesn't mean they are exactly the same as the old carbs.

 

[varg24]

Well I was able to swap the needles out last night, but my pop-off pressure is way too high according to my sheet. My sheet says I should be around 32 Psi with the shiny spring, and I am well above 40.

I am pretty sure the jets are the same on both my old and new sets, and I put the new needle and seat in the new set. I have only tried the MAG side so far, but am I doing something wrong? I am hooking air to inlet hose and I have to block off both the outlet and pulse lines. I sprayed the needel with WD-40, and I am popping at around 42-45 PSI.

Anyone have any ideas on what do do to get it down to 32? Maybe 42-45 is fine?

 

[Lifted5.4Lariat]

I think you clip 1/2 of a turn to get the pressure down.

 

[Dr Honda]

Did you verify that the needle and seat are the right size? That may sound basic, but I just wanted to know.

Also... if the springs are aftermarket... they may not be right.