2005 Yamaha 90hp tiller 4-Stroke Belt and Torque

Repair or modification of Boston Whaler boats, their engines, trailers, and gear
Iceboy149
Posts: 15
Joined: Thu May 03, 2018 6:05 am
Location: Crownsville, MD

2005 Yamaha 90hp tiller 4-Stroke Belt and Torque

Postby Iceboy149 » Wed Jun 03, 2020 10:05 pm

Hey guys,

I'm working on a friends 2005 Yamaha 90hp 4-stroke tiller and it had water in the bottom cylinder. The motor is so beat up that most would of thrown it to the scrap bin but I couldn't bear to do it so I took it apart and had the head repaired and got it all torqued back into place but the torque values I'm missing are:

Oil Cover Seal?
Cam shaft Retainer Covers (There's 4 of them for each camshaft)

Also when reinstalling the timing belt, the cam gears have nice arrows as to where to position them but the flywheel only has TDC and then TDC with the 10/20/30 degree advance/retard markings. Is the TDC and small adjustable timing arrow on the block my reference point to set the belt to, or do I need to pop the flywheel off?

I know I should invest in the manual but this motor is being retired to a 50' houseboat and will be started twice a year to bring it from the end of the dock closer to the showers for the winter and then when summer hits back to the end of the dock. Hence my not wanting to spend a ton of money on it. So far I'm in for $380 including the welding and head shaping, four valves, head gasket, thermostat, and anodes.

Thanks, Dave