'91 Yamaha 175 - shift shaft sheared

ctone

Recruit
Joined
Oct 3, 2004
Messages
1
The shift shaft on my '91 175 Yamaha sheared just above the lower unit. It was badly corroded at the point just above where it goes into lower unit. Bottom of shaft has a fixed barrel fitting that slides over geared fitting on lower unit. Not sure how top end is mated. I've removed the grease bearing so it's loose enough to pull out vertically but there's not enough clearance between the lever and the powerhead to get the lever out with the shaft still attached to it. I would think that the top end of the shaft is mated to the lever in a way that would allow the shaft to be disconnected from the lever so that the shaft could be removed from the bottom side after disconnecting the lower unit. However, the shaft looks to be welded to the lever. If that's the case, the only way to remove it would be to cut it just below the lever, or remove power head. Both options suggest a serious engineering design flaw. No corrosion at all in that area so I know it isn't just corroded in place. I've removed the grease bearing around the top end of the shaft and I still can't see how the shaft attaches other than the weld spot on top of the lever. Anyone know if the shaft was designed such that it can be removed without pulling the powerhead? If not, anyone know if the replacement part can be installed without pulling powerhead (it's listed as a new "different" replacement part.<br />Ctone
 

rodbolt

Supreme Mariner
Joined
Sep 1, 2003
Messages
20,066
Re: '91 Yamaha 175 - shift shaft sheared

hello<br /> gotta pull the power head. oxy/acetylne and prayers. I am finnishing a 91 225 this week that I had to cut the powerhead adapther. if you have many stuck or broken bolts post back and I will tell you how to cut them.<br /> good luck and keep posting
 

Adman5

Cadet
Joined
Jul 31, 2005
Messages
13
Re: '91 Yamaha 175 - shift shaft sheared

Originally posted by rodbolt:<br /> hello<br /> gotta pull the power head. oxy/acetylne and prayers. I am finnishing a 91 225 this week that I had to cut the powerhead adapther. if you have many stuck or broken bolts post back and I will tell you how to cut them.<br /> good luck and keep posting
 

Adman5

Cadet
Joined
Jul 31, 2005
Messages
13
Re: '91 Yamaha 175 - shift shaft sheared

Have sent you another posting re 92 225 with 5 of 6 bolts snapped off, but in case you didn't get it, what is your best advice as to cutting through adapter and where can I find new one and new shift rod?<br /><br />thanks for any help/advice
 

rodbolt

Supreme Mariner
Joined
Sep 1, 2003
Messages
20,066
Re: '91 Yamaha 175 - shift shaft sheared

use a 1/2 or 3/8ths bullet point drill bit and drill horizontally as close to the power head as possible in line with the bolt and cut the bolt.<br /> thats just the start of the fun. once its cut off do the same just above the adapter to midsection and remove the adapter . to remove the adapter/muffler assy will require the midsection to be removed from the swivel bracket assy. your looking at 400 in parts and 10 -15 hours worth of work. any yamaha dealer can order the parts for you. my suggestion is get a factory manual and look at the exploded diagrams to see how it goes together. you will not get much on how to dissasemble it. the new shift shaft is stainless<br /> wish the old ones had been<br /> killed many a good motor<br /> I think in 95 they realized the failure and changed it to stainless.<br /> good luck and feel free to post questions.
 

Adman5

Cadet
Joined
Jul 31, 2005
Messages
13
Re: '91 Yamaha 175 - shift shaft sheared

Originally posted by rodbolt:<br /> use a 1/2 or 3/8ths bullet point drill bit and drill horizontally as close to the power head as possible in line with the bolt and cut the bolt.<br /> thats just the start of the fun. once its cut off do the same just above the adapter to midsection and remove the adapter . to remove the adapter/muffler assy will require the midsection to be removed from the swivel bracket assy. your looking at 400 in parts and 10 -15 hours worth of work. any yamaha dealer can order the parts for you. my suggestion is get a factory manual and look at the exploded diagrams to see how it goes together. you will not get much on how to dissasemble it. the new shift shaft is stainless<br /> wish the old ones had been<br /> killed many a good motor<br /> I think in 95 they realized the failure and changed it to stainless.<br /> good luck and feel free to post questions.
 

Adman5

Cadet
Joined
Jul 31, 2005
Messages
13
Re: '91 Yamaha 175 - shift shaft sheared

Thanks for your advice. Motor ran well with about 1000 hrs on it (Actually its 1990). From your reply, looking at about $1500 or so job to get my motor back. Would love to hear your opinion on whether its worth it or time to call it quits. If you were looking at used 225 or 250 Yamaha, which years/model would you recommend and what hour range. I just don't think I'm up for extra weight of 4 stroke or the unknowns re new models (in addition to price!) Thanks again.
 

easygo0

Seaman
Joined
Apr 4, 2004
Messages
59
Re: '91 Yamaha 175 - shift shaft sheared

adman give it a try, got nothing to lose just get a good manual first.I spent about 100 bucks on 25" shaft first time around and got lucky on bolts.took my whole saturday though just be ready with torch and drill just incase.I used hvac duct hoist and choker to raise powerhead.easily rented 25.00. Ive seen shift shafts on e bay (boatparts1) for around 20.00 good luck and look at bright side you could be back on water following weekend.sorry cant type worth a @&?/# but love to tinker.
 

rodbolt

Supreme Mariner
Joined
Sep 1, 2003
Messages
20,066
Re: '91 Yamaha 175 - shift shaft sheared

I am with easygoO<br /> if your going to scrap it anyway give it a shot. just always remember dont damage the power head surfaces or the exhaust housing. the adapter is scrap so thats where to make all the cuts.<br /> all the holes are tapered and larger at the top than the bottom so alawys drive the broken parts upwards. once the powerhead and gearcase is off you will remove the upper and lower mounts and then the powerhead adapter from the midsection. then seperate the exhaust tube from the adapter. order what bolts ya need with the shaft and adapter assy.
 
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