Yellow 580 to White engine swap-Need a little help

[Musicmanjer]

Hey All,

Been a while since I've been on this site, but finally got to start my resurrection project of a '91 GT. I'm custom building this ski specifically for our USCG Auxiliary safety patrol OPS for the river and Lake, and am looking forward to getting it done. The original yellow 580 blew a rod when the injection pump failed, so its toast. I have a '93 White 587 motor with 140 psi in both jugs that has never been cracked open from a ski that was salvaged and demo'd.

1) I've read a few threads here on the swap that says the white motor can be used, but the 580 flywheel, stator, etc. need be installed on the white block. What will I run into by doing so? Timing? I recall tapping threads for bolts?? i believe Dr. Honda said something about this?

2) I understand the cooling setup is different/better on the 587, but how do I adapt the hull for the hose in/out differences?

3) PTO Shaft alignment; After installing the motor, I've read about installing the shaft and cranking the starter to align, but what about shimming?

4) The yellow motor had dual carbs that were rebuilt and the cables are still attached with the intake ass'y. The white had a single carb. Can I use the yellow dual intake on the white single OR should I figure out how to adapt the cables for the single carb? Airbox difference??

I know, long winded and a lot of questions. Alright thanks very much in advance for the advice. I know these are old ski's, but when our Government gives us a budget of lemons for equipment, you gotta make lemonade

 

[Dr Honda]

1) You will either have to use all the electronics from the yellow engine, or the white. SO yes, that would mean putting the mag, and flywheel from the yellow to white. I don't remember if you have to drill/tap anything. (Sorry)

2) If you use the pipe from the white engine... just rout the tubes via the newer ski.

3) There was 2 different belly pans. Unfortunately, you will have to just mount one up... and check the alignment. With the kind of swap you are looking at doing... you can't really do it without owning a seadoo alignment tool.

4) Absolutely. Just bolt on the manifold, carbs, and all the parts from the original ski, and it should run fine.

 

[Musicmanjer]

Thanks Tony,

If I read correct, the yellow 580 actually has a hotter spark than the white 587? To simplify things, I think I'll use the yellow flywheel etc. and exhaust system because it looks like if I put the yellow flywheel case on the white motor, the exhaust riser for the white might hit the case?? Not sure but I'll find out quick!

The belly pans look to be the same, so I might have lucked out. as far as the carb, looks like I'm good to go.

BTW, have the Ebay carb kits gotten any better or should I stick to the Mikuni kit? I have another ski that needs a rebuild.

So it looks like an alignment tool is about $200. Can I use anything else?? I realize there's no substitute for the original, but since this is a low budget build, i'm limited.

Thanks for your help with this. As I build it, I'll post photos. Should be a cool project.

 

[Dr Honda]

Yes... always use OEM Mikuni kits. Don't use aftermarket kits, since they almost always have running issues.


You can try to align it "By Eye"... but if it's out too far... you will

a) Bend the driveshaft
b)Throw the shaft
c) wear out the splines.


I know the tool is expensive... but since you aren't bolting the original parts back in... you don't even have a baseline to start with. You need the tool.


FYI... check SBT. They use to rent one, but it will still cost $70 with the shipping. Your best bet is to buy it from STB, and then just sell it when you are done. Guys will buy them in a hart beat for $100. So... you will only be out $50.

 

[Musicmanjer]

How many times have you clicked "reply to thread" instead of "post quick reply" !! Darn it!!

Ok, so I thought so on the Mikuni kits. Nothing worse than ripping out carbs, rebuilding them, reinstalling just to find out you have a bad diaphragm new out of the package. Mikuni's are 2x the cost, but at least they're proven good OEM parts.

Great idea on the alignment tool. I did just that with my Mercruiser Gimbal bearing tool. Ended up costing me $25 in the end. Any idea the best place to get one??

Thanks!

 

[68ragtop]

I made a simular swap years ago. There is something different between the mag housings if I remember correctly. I think it might be the bolt hole pattern that secures it to the block. I went the other way tho. I put a yellow motor in a white powered ski. I ended up using the yellow mag housing because the white didn't fit for some reason. But seeing you are going the other way, maybe it will work? I think you need the yellow housing because its larger & holds the coil & other parts that are external on the white motor? My memory is a bit grainy.

 

[Musicmanjer]

Thanks 68Ragtop. I think youre right about electronics. I'll crack it open this weekend and see what im up against-

 

[Matt Braley]

There are four bolts that hold the yellow engine mag cover to the engine case. The bosses are there in the white engine but not yet drilled and tapped because they had smaller bolts in a circle pattern holding the white mag covers on.

 

[Musicmanjer]

Thanks Matt. I knew there was something I had to do to adapt the bolts. So, can I assume it's self explanatory that I drill and tap the 4 holes that line up with the housing? Also, was there an issue with clearance on the yellow case hitting the white motor exhaust riser?

The rubber grommets for the coil wire and plug wires are badly rotted and don't seal. Are their replacement grommets anywhere or is the motor too old?

Thanks again!