787 MAG carb question

[lakeeriejoe]

I have watched videos and read the carb rebuild sticky on here and have seen zero mention of this. My MAG carb has THREE adjustment screws; the high side, the low side, and then a third with no needle/point end and has a T handle like the low side adjuster. It pushes against the closed butterfly and if you adjust it in so far it starts to push the butterfly open...if you crank it all the way down the butterfly is open pretty good. When i took it off during rebuild (thinking it was the low speed adjuster) i counted 8 1/4 turns out from all the way in. If i leave it there, it won't be pushing on butterfly at all...is this accurate? What is purpose of this adjustment screw?

 

[etemplet]

It is your idle adjustment screw. When you connect the throttle cable make sure you have slack in the throttle. 1/8" is sufficient. the throttle has to close all the way. You then adjust your idle. You'll also have to set the oil pump throttle.

 

[lakeeriejoe]

It is your idle adjustment screw. When you connect the throttle cable make sure you have slack in the throttle. 1/8" is sufficient. the throttle has to close all the way. You then adjust your idle. You'll also have to set the oil pump throttle.View attachment 62645

Thanks! What do you mean by "set the oil pump throttle"? I have also heard about lining up "oil pump marks", is that what you are talking about? If so, where are these marks?

 

[burtshaver2021]

The red lettering shows the alignment marks

 

[lakeeriejoe]

View attachment 62647The red lettering shows the alignment marks

Thanks! So if marks arent lined up, i need to adjust the nuts on the cable down near the carbs one way or the other?

 

[burtshaver2021]

That’s right

 

[etemplet]

View attachment 62647The red lettering shows the alignment marks

Great Post !!

 

[burtshaver2021]

I

Great Post !!

I stole the picture from @mikidymac

 

[lakeeriejoe]

So I am in the midst of re-installing carbs. Prior to getting them inside the ski and connecting the cables, I took the attached pics. Based on the pic posted by @burtshaver2021 (or @mikidymac), and seeing how mine is a bit beat-up, is the blue circle in my pics the mark on the lever control and is the red circle where the notch/mark "should be" on the pump? If I am correct on the lever, that is pretty easy to spot...however I am just kind of guessing on where the mark on the pump should be based on the pic that was posted with labels...i don't actually see it in these pics. However, if that is where it should be, not at least I know where to focus.

 

[lakeeriejoe]

I just watched a Youtube video on the 787 oil pump adjustment and since I don't have the cable even hooked up yet on the carbs, the lever is well away from the mark and is on the bottom of the pic, see attached...is that accurate? Again, hard to see due to its condition...hoping I can clean up both marks with a wire brush and/or some cleaner prior to final adjustment.

 

[Grim]

I just watched a Youtube video on the 787 oil pump adjustment and since I don't have the cable even hooked up yet on the carbs, the lever is well away from the mark and is on the bottom of the pic, see attached...is that accurate? Again, hard to see due to its condition...hoping I can clean up both marks with a wire brush and/or some cleaner prior to final adjustment.

Yes, there is spring pressure on the lever. when you hook it up to the carb it will pull against the spring to align, hopefully, at the mark.

 

[lakeeriejoe]

Yes, there is spring pressure on the lever. when you hook it up to the carb it will pull against the spring to align, hopefully, at the mark.

Thanks...so what I circled in blue on that last pic is the mark on the lever...and the red circle on the other pics is where the mark on the pump should be?

 

[Grim]

That looks right, the system is designed to go wide open if the cable breaks, preventing you from burning up the motor. Wont know if it aligned until you reconnect the cable.

 

[lakeeriejoe]

That looks right, the system is designed to go wide open if the cable breaks, preventing you from burning up the motor. Wont know if it aligned until you reconnect the cable.

Can you tell from these pics if marks are lined up?? No idea what i am aiming for here since lever is so beat up

 

[Grim]

Can you tell from these pics if marks are lined up?? No idea what i am aiming for here since lever is so beat up

Cant tell, try and clean it off with something. or at least scrap the alignment marks to see them better.

 

[burtshaver2021]

I exploded the view from your one picture, you can see the line on the oil lever arm and there should be a line in the protruding piece with the blue mark on it. Looks like you would need more oil the way you have it now.

 

[burtshaver2021]

Is this machine an RFI because it looks like you have 2 lines on the oil lever? I read somewhere that the RFI’s have 2 marks, 1 for regular operation and 1 for the break in period.

 

[burtshaver2021]

after looking again I think the top line on your oil pump lever is just a scratch, it’s not straight. Line up the blue lines in the picture I posted. As Grim said if you clean off the lever and protruding piece of metal on the pump with a little 600 grit paper you will see the line more clearly

 

[lakeeriejoe]

No, just a 97 GTX. After using some brake cleaner and a stiff brush, I was able to see the marks a lot better and think I have them lined up correctly.