Bulletproofing 3D DI

[Shane0306]

Hi all, I have just purchased a 3D Di

It needs honing and new Pistons as apparently one of the oil lines became blocked?

I pick it up this weekend so I can assess the damage, I intend to do a full rebuild, change to a solas prop, move battery and clean up anything that isn't right.

I was wondering, if anybody has suggestions or recommendations to keep the DI running smoothly, I hear they are very problematic?

I'm sure everyone has a tip or two to share on how to keep this 130hp beast on the water instead of in pieces.

Shane.

 

[Sportster-2001-951C-Stock]

Using the correct type oil is probably most important, that and fresh fuel not old stale skunk pee.

The DI's run sweet I'm told, when they're running correctly. Most of the challenge beyond that is discovering where the problems are, absent blowing a boatload of money by shotgun troubleshooting.

I'll just say, most 2-strokes lose a piston either due to being worn out normally OR problems with getting good fuel in correct quantities. Of course lack of maintenance and mixing incompatible TCW3 outbored engine oil with correct API 2T Seadoo XPS Sythetic oil will congeal to jello in the tanks and lines thus starve motor of lubercation.

 

[Shane0306]

Using the correct type oil is probably most important, that and fresh fuel not old stale skunk pee.

The DI's run sweet I'm told, when they're running correctly. Most of the challenge beyond that is discovering where the problems are, absent blowing a boatload of money by shotgun troubleshooting.

I'll just say, most 2-strokes lose a piston either due to being worn out normally OR problems with getting good fuel in correct quantities. Of course lack of maintenance and mixing incompatible TCW3 outbored engine oil with correct API 2T Seadoo XPS Sythetic oil will congeal to jello in the tanks and lines thus starve motor of lubercation.

Thanks sportster, I have heard that it's very important to use correct oil also, I have already purchased xps full synthetic 2 stroke and that's all I intend to use. I intend to strip the beast back and re build pretty much everything and use the right stuff in it and hopefully that works, but I have heard of a few people doing a full rebuild and only being 3-4hrs in and seizing on the 947/951 DI.

I'm excited but nervous!

 

[Sportster-2001-951C-Stock]

Agreed, and you'll need to be meticulous with the mechanicals of course. Fuel pumps and injectors being old and perhaps clogged are show stoppers, maybe you can test them or have them checked. Basically if it runs smoothly and makes good power you should be okay but even in that case if one cylinder has a leaking injector it can wash away the oil film due to excess fuel despite seemingly running well otherwise.

Keep an eye on the spark plugs, black fuel soot on one while the other looks good might be sign of a leaky injector and while running on the trailer the plugs will run cooler than normal thus they'll look rather sooty.

[MENTION=57696]68ragtop[/MENTION] has rebuilt a few from the ground up, he's been there done that I guess you could say.

 

[Shane0306]

Wow that's true, I never thought of that, that kinda sucks! You would never even know the engine isn't getting the right lubrication until it's too late!!
do you know if you can convert D.I to premix? At least that way if it's running you know oil is getting there.

 

[ski-d00]

You can't convert a DI to premix. It will ruin the motor very quickly. You can't add oil to the gas at all as it will clog the fuel injectors and there is no point. Fuel is added directly to cylinders in a DI and it must get oil to the crank and the only way it can is through the injected oil. Most people who add oil to the fuel after a rebuild ends up blowing it up.

You don't have to move the battery on a DI, it's in the back and not in the front like the rfi.

 

[Shane0306]

I looked into it s bit and read the same as what you just said, so I have replaced every oil line with brand new tube, cleaned out every fitting, cleaned the oil filter, tested that it's working, I'm not giving it a reason to not work.

Yeah I see that now, it's in an okay spot.
However I'm changing it to a lithium ultralight battery weighs only 600 grams, compared to the 7kg lead acid that was in there