9.9 Yammy Stuk Drive shaft?

[Spaniard_King]

Doin a small job for a mate, hoping for a miracle from someone.

Early 90's Yammaha 9.9hp, symptoms are unable to turn engine over Suspected Lower engine main bearing failure.

Pull starter checks out fine. Neutral start mechanism OK
Removed cylinder head > pistons are free in the bore
Undone all gearbox bolts and shift rod > unable to remove gear box from engine
Removed all power head bolts/and all associated attachments, outcome of this > Unable to seperate powerhead from midsection

Before anyone asks, I have not forgoten to un do something. Last time I did one of these was a 70hp johno had to cut through the drive shaft with a 4 inch grinder to seperate the powerhead from the gearbox, then had to dissassemble engine send crank to machinist who removed the drive shaft spline from the crankshaft. Once you add all the parts up and labor it's hardley worth it. Other than hanging it by the powerhead and waitin for it to fall appart

I was hopin someone had a little miracle to help me out as I dont wanna take to the midsection of this one with a grinder, we were able to get good access to the old 70 hp drive shaft but this one is enclossed in the middsection.

cheers

Garry

[finga64]

I've seen guys drill a big hole in the side of the leg extension and then cut the drive shaft. Rough as a porkupine's back, but the legs off
Sounds like a project to think about over an ale or seven

[NQCairns]

Hi Garry, Just got a coffee then deleted my former post because I didn't read yours properly
Here is a sure fire way to get it of.

I am assuming you have some gap??

First bolt the powerhead up solid to correct any lateral movement under pressure.

Then

Looking at the leg from the side mark where the drive shaft runs top to bottom. Ascertain which bolt or bolts (better but they should be equal distance away) is the furtherest from the shaft, all other bolts should be out. I will assume it is a bolt at the rear.

Loosen your chosen bolts of enough so that you can force the lower leg forward by hand enough to open the gap like a wedge ie thin at the front and widest toward the rear.

Place a piece of wood or anything that will serve the purpose right through the gap from side to side and as close to the shaft as possible - thats important!!! it should be a nice firm fit and must be between bolt and shaft but closest to the shaft. If you cannot get something right through and close to the shaft a piece either side is the next option.

Start torquing the bolt/s up, this will force great pressure upon the drive shaft and in a fairly straight pull.

Slow and steady wins here, you may need to keep placing thicker wedges in as you work it out, the first pull may only give you an extra mm to play with next time.

Garry this always works, take your time, would have on the 70 also I am sure, keep that grinder covered in cobwebs for a little longer [smiley=2thumbsup.gif]

Good luck with it. nq

[finga64]

Good idea!!! I'll have to remember that one

[Spaniard_King]

NQ,
mate nuthin would have worked on the 70, trust me it was a shocker

As far as the 9.9 goes, the drive shaft was siezed in the lower seal assembly on the engine. All appart now . Lower bearing and seal was OK. After haven chatted to a Yammy dealer he tells me this is a common problem with the 9.9. I won't let out how I got her appart although(those rattle guns are bl**dy handy ) NQ your suggestion would have worked I recon.

A good reason to turn her over every so often I guess

Garry

[NQCairns]

Garry good to hear you got it apart/started, there's always something extra to do on a sat engine.
You rattled the flywheel nut, does sound like the start of desperation setting in when thoughts like that pop up while looking at a problem engine cheers nq

[Spaniard_King]

nq, turned her over with a breaker bar first, to my surprise the gearbox started to drop. my arm got sore so out came the rattle gun

Happy with the outcome

Garry