I have a Sears Ted Williams 7.5hp water cooled ??twin cylI am looking for any info I can find on this motor ie. plugs, proper mix, parts etcThe model is 57460121 Serial is 656600711 9941The motor is in great shape for it's age I ran it last season with the Champion H 10 C plugs that were in it when I got the motor, fuel was 40 - 1 mix I just changed the oil in the bottom end, the plug had the word "grease" stamped above it I drained and refilled with regular outboard gear oil.The motor has not seen the water or been started yet this year, I have been looking for proper information before I run it.I am also wondering if there is anything else I should check/replace before my family and I enjoy this old workhorse for another summer Thanks Rob
Only things that comes to my mind are w/p impellers and the fuel pump diaphragm... I wonder if the diaphragm is 40 years old. Laing's outboard parts has new ones (see Mcculloch), but of course you have to pull the powerhead out of the case to get the carb off... I have that down to a 20 minute job, but the first time.. wow...what a crappy way to design something. It goes something like this...:Pull flywheel, remove timing advance linkage, remove fuel line to carb - swear a bit... - pull 1 spark plug, remove the top nut of the FNR shift linkage (PUT IT IN R AND LEAVE IT THERE IF IT'S A WEEDLESS LOWER UNIT!!) pull the linkage and other nut off the shift rod. Remove all screws, pull power head...The diaphragm is sandwiched between the bottom plate of the carb and the throttle body...the w/p impellers... they are fiddly farty too.. I'd probably leave them if the thing spits a good spray of water out the exhaust ports.. something with the keyway was really ticking me off when i did my one 7.5Your gear lube looked good? I ended up putting a copper washer in behind the propshaft seal on my weedless lower... fixed it's chronic water ingestion problem- the snap ring just didn't hold the seal tight enough before and it would puke it's lips out..that sounded gross, but that's what it did...
The oil in the bottom end was very dark (old)so I have no idea how long it was in thereI picked up the motor last year and ran it before the summer ended.There was no sign of water in the oil The only issues I had with it was once in a while it would slip out of gear maby 4 times all summer I have contacted the scott guy for a manual before I get too far into this motor I was thinking about a new prop, there is a little bit of play on the existing one and I think it might be slipping is it a common prop ? what size do you recomend ?Rob
It's a shear pin prop..take spare pins and pop the cone off to see how they change.There is a lot of backlash in those lower units, that might be your "play".Dark oil is fine. Just change it a couple times a season - 90 wt.I wouldn't change the prop unless it's damaged.