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  1. #1

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    Need someone to retard 951 di for me.

    I live in eastern NC, greenville area. and I was looking to see if there was anyone within a reasonable range that has the software to do this for me before I go to the stealership. I am about to finish the rebuild, and from what I read it is best to retard it 2 degrees for survivability.


  2. #2
    diamondwatercraft's Avatar
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    Interesting concept. Where did you hear about doing this?

  3. #3

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    Found it online. Let me try and dig up the article

  4. #4

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    Ok, it was on another forum, and so as to not link to them, let me just do a c/p on the relevant The DI is a different engine as it has some different quirks about it. For some damn reason I have seen new DI motors snap off the ring lands right where they pass the exhaust ports. This is not all that uncommon on new motors, but even more likely on a rebuilt engine. When, for whatever reason, the bore size is increased past .25 oversized, the ring land snapping is likely to happen, and in trying to get a real answer to the problem is about like the chances of hitting the Mega lotto for $300 mil. We know about trimming back the rave valves, but even overdoing that is of no help.

    We tried extra piston clearance and we cracked piston skirts off. Forget that method, it does not work beyond an extra thou. of clearance. In fact, DI's hate too much piston clearances, more so than carbureated engines.
    We tried a thicker head gasket, still had the problem. Finally, someone smarter than myself, decided to retard the initial timing a degree or two, and as long as the overbore did not substaintually increase the compression ratio by more than about .2, running on 91 octane pump gas and the oil injection only, with an extra thou of piston to wall clearances honed into it, it lived. The next one lived too, and the one after that one. No such ring land failuers that I know of to date

  5. #5
    This is how I run a jetski shop in the desert nmpeter's Avatar
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    somewhere I recall reading that Seadoo only offered 1 o/s piston [email protected] .25

    951's ain't dying fast enough for me.

    Had some new owner sticker shock @ the shop selling synthetic oil this weekend ( say that real fast whydon'tyou)

    They tried to squeeze every drop out of the 961, I'd certainly try going back 2 degrees, just for grins if I happened to own a 951 myself..which I do..but I needs a complete engine rebuild and I can't justify the cost based on the book value..so I keep her around to verify a bad sensor before I go and blow a customers money and my time on a defective diagnosis.

  6. #6

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    I did 6 di complete rebuilds last year from .5 mm to 1.5 mm over bore and ran 5 hole base gaskets on the .5 and 1.0s and 6 holes on the 1.5s. Still going strong with no issues with rings or pistons coming apart-- there were other issues that needed to be addressed thou.

  7. #7
    diamondwatercraft's Avatar
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    This is some real technical stuff here! I have had my share of DI failures. (usually counterbalance shaft gear to crankshaft gear)

    How would the dealer retard the timing?

  8. #8

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    Apparently buds can be used to adjust the timing on this model. It can not be done mechanically.

  9. #9

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    Jim, do you add any oil into the fuel during the initial break in? What octane do you use?

  10. #10
    Derek45's Avatar
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    well thats stage if BUDS can why Candoo cant???? anyone???

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