Pop off pressure

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andrewterri

andrewterri

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Getting the carbs built and getting a pop off of about 37 with new springs. Old spring was 60 on mag and couldn't get a pop off while using pto spring on mag carb. No old pop off before rebuild because needle was stuck to seat on both carbs and mag carb needle had a broken metal bracket the pivot arm goes through. My question is, is have a 37 pop off when the guide states it should be 36-62? I think 62 is the high number, it might be 60. The ski is a 96 GOT with 717 and twin bn-38 bikini carbs. What would happen with a pop off at the bottom limit
 
Yes, your pop off should be 36-60 with 1.2 needle and seats. The big issue is both carbs should be exactly the same if possible. Also the needle and seat need to be wet, I use WD-40. Put a paper towel over it so it doesn’t pop in your face.

Give me a minute to check on springs.....

Your ski takes the 95 gram springs. If your old ones are good use them. They should measure 15.85mm
385d81178fc716698304f76c83a3a461.jpg


The kits come with the wrong springs 65gm and 115gm.
 
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Both spring are exactly the same, at least on the mag carb. I was worried being on the low end would effect performance or make it too rich. Dumb question, but the front jug closest to the handle bars is the mag and the jug closest to the pump is pto correct?
 
That's awesome thank you. I tried calling Westside twice today and could not get a hold of anybody. Still can not find that carb base gasket. No one list the size and as you showed me i need a 44mm id. Same part number crosses for the 4 gaskets I have and the 787. I think seadoo used the smaller intake manifold when they went back to single carb on the GTI in 97 and that's why the gaskets I have show they are for the 96 through 2002. How can I order and verify I'm getting a 44mm I'd? This is crazy, I have never had problems like this ordering parts. I have even went to 2 different parts diagrams and get the same part number and that shows its for the 717 and 787 but it's not.
 
No, the single carb 720 1997+ use the same gasket as yours. But is 2001ish they got thicker.
277ba49be77251b631e6b71a7d2460d7.jpg


Just order the gaskets for a 787, seadoo number 293250134.

The measurements are confusing because they are a taper bore carb, they start as 44mm and taper to 38mm but are based on the Mikuni 44. The actual 38mm Mikuni is physically smaller then the smaller gasket.
 
If you can’t get the gasket I can mail you two if you have to have them now then replace them to me once you get the correct ones.
 
That makes sense now. I don't need them right now I am just being impatient, but thank you very much for the offer. I can't stand not having something completed and ready to go.
 
I used the springs in the kit (dark silver). Mag carb pops at about 37 and pto at 39. The springs that were on the ski had 58 on mag and somewhere over 65 on pto. Never could get pop off for pto with that spring. The new shiny silver spring from the kit were popping at 25. Read a post by dr.honda that going low is okay just might need a low speed adjustment to compensate for being rich. Worst case I will order the spring you said and which them out.
 
I would measure the new springs to confirm that they are in fact the 95 gm springs. I don't remember if the kits come with the 115 gm or the 95 gm springs. I could open one tonight when I get home.

The 95 gm springs will measure exactly 15.85 mm as I posted above. You will have issues using the wrong springs even if pop off is within the "range".
 
Believe it or not that is the one tool I don't have, a micrometer. I need to order one. The kit came with a dull silver and shiny silver spring. I need to look at your chart again but I think dull silver is 95 gram.
 
Believe it or not that is the one tool I don't have, a micrometer. I need to order one. The kit came with a dull silver and shiny silver spring. I need to look at your chart again but I think dull silver is 95 gram.
 
The colors are hard to tell in my opinion. You can also use a good ruler since it should measure 5/8".

Harbor Freight has the micrometers for about $10.
 
According to the chart you posted with the spring weights. If the way I am looking at it is right then starting with the far left, shiny silver 65gr, dull silver 95gr, black 80gr, and gold 115gr. The mikuni rebuild kit I got has the shiny silver and dull silver. I used the dull silver and got about 38 psi if you average both carbs together.
7d6424cb3f4b403e0f077deccdc5aa00.jpg
 
If you used the correct 95 gm spring and are within the range and a couple psi between carbs you will be fine.
 
Thank you, i have been under the wrong impression. The two left ones are identical to what I got but didn't think mikuni included a 115gr spring. I am going to go ahead and order 2 95gr springs now with my new fuel baffle to fix the fuel gauge. I will try the ski now and see how it runs since I'm with psi range and think I am using the 95gr spring; if it runs bad I will switch them out and if it runs good I will have them for 95 spx when i rebuild those carbs this spring. When i checked the pop off i had the check valves on and used the fuel inlet line while plugging the transfer and return line. That will still give me the same psi as checking it through the fuel filter hole right?
 
Yes. You checked correctly. Typically you can fix the fuel sending units by removing the F1 fuse.
 
Pretty sure that’s what it is. It’s at the top of the baffle. I cut a window into it with a utility knife, remove the fuse and bridge the gap with solder. Works every time. The test is with a multi meter see if the resistance changes when you tip the sending unit upside down. Then use the soldering iron to melt the window you cut back in place.
211fdc4d14968a0778cf6e437ba15977.jpg
 
Once I get the tank drained tonight I am going to pull it forward to get the baffle out. Does the mutilmeter prongs go where the fuse sits when I pull the fuse out? Trying to search and find a write up but I'm at work and my boss does not have his priorities right, he keeps wanting me to work :)
 
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