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#1
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Yamaha Outboard Timing help
Hi I have just aquired a cheap Yamaha Outboard which I am in the process of servicing. Can any one tell me the appropriate points gap and timing degrees for my 8HP Yamaha, Model 8B, serial number 677S005141 I believe its 1977? It would seem to be impossible to buy aSeloc or Clymer manual for a 1977 Yamaha, would a Mariner Manual for that period cover this model as I understand Yamaha used to make some of the older Mariners ? I would also appreciate any links for further information on this engine. Thanks Chris -- Chris Selwyn-Smith (M0CGW) www.chrisss.demon.co.uk |
#2
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Yamaha Outboard Timing help
Aloha Chris,
There is a manual called "Outboard Motor Service Manual: Covering Motors Below 30 HP from 1969". Check it out at www.marineengine.com. Key in 8 hp yamaha in the search area for engine manuals. Hopefully it has the specs you're looking for. Ken Tanaka Pearl City, HI "Chris Selwyn-Smith" wrote in message . 254.254... Hi I have just aquired a cheap Yamaha Outboard which I am in the process of servicing. Can any one tell me the appropriate points gap and timing degrees for my 8HP Yamaha, Model 8B, serial number 677S005141 I believe its 1977? It would seem to be impossible to buy aSeloc or Clymer manual for a 1977 Yamaha, would a Mariner Manual for that period cover this model as I understand Yamaha used to make some of the older Mariners ? I would also appreciate any links for further information on this engine. Thanks Chris -- Chris Selwyn-Smith (M0CGW) www.chrisss.demon.co.uk |
#3
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Yamaha Outboard Timing help
"Ken Tanaka" wrote in
: Aloha Chris, There is a manual called "Outboard Motor Service Manual: Covering Motors Below 30 HP from 1969". Check it out at www.marineengine.com. Key in 8 hp yamaha in the search area for engine manuals. Hopefully it has the specs you're looking for. Thanks for that I have just ordered it from Amazon thanks for the info -- Chris Selwyn-Smith (M0CGW) www.chrisss.demon.co.uk |
#4
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Yamaha Outboard Timing help
Thankyou for all that
There are degree markings on the fly wheel from +10 to -30 and yes it does have points. I have checked out the parts diagrams available from the US Yamaha site for the 84 8 hp model. http://www.yamaha-motor.com/products...p?lid=5&lc=otb then the Parts and service menu parts catalogue I dont think the process is quite the same on my motor as there is no adjustable link rod or any adjustable stop. however thankyou very much for your interest and help Chris -- Chris Selwyn-Smith (M0CGW) www.chrisss.demon.co.uk |
#5
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Yamaha Outboard Timing help
Chris Selwyn-Smith wrote:
Hi I have just aquired a cheap Yamaha Outboard which I am in the process of servicing. Can any one tell me the appropriate points gap and timing degrees for my 8HP Yamaha, Model 8B, serial number 677S005141 I believe its 1977? It would seem to be impossible to buy aSeloc or Clymer manual for a 1977 Yamaha, would a Mariner Manual for that period cover this model as I understand Yamaha used to make some of the older Mariners ? I would also appreciate any links for further information on this engine. Thanks Chris Chris, The earliest I can find in this place is for the 84 model so this might be a total waste of your time, but being another Smith you'll appreciate me trying to help anyway:-) It seems by 84 anyway they no longer had "points" & other than the very little motors neither did the other brands, so I'm wondering if your engine has points?? (i) Check to see the timing pointer does actually point to TDC particularly with older carryable engines, it might be bent, moved etc. (a) Take the spark plug & break the porcelain centre out if it (you'll be giving it a new plug anyway??), put a small nut & bolt through the hole where the plugs' insides were so the tail of the bolt will hang into the combustion chamber a little way & stop the piston getting to TDC. Put in in the head finger tight with the piston down the bore. (b) Carefully & slowly by hand turn the flywheel till the piston just touches the bolt. Mark the flywheel (scribe? but a pencil is fine) where the TDC pointer is pointing. Again carefully & slowly by hand now turn the flywheel the other way so the piston goes down then will again contact the bolt tail on the way up again. Mark the flywheel where the TDC pointer is now pointing. (c) With a tape now measure the distance between your two pencil marks on the flywheel, The pointer in it's current position is pointing to TDC exactly halfway between the two marks, which if everything is as original will also be where the flywheel is marked TDC, if it isn't; then you can bend or move the pointer so it will be. (d) Repeat the process just to be sure the pointer does actually point to TDC. TAKE THE PLUG WITH THE BOLT IN IT OUT NOW, BEFORE YOU FORGET & TRY TO TURN THE ENGINE OVER WITH IT STILL THE-) (ii) The max advance for the 84 model is 35 deg BTDC the amount of spark retard (ATDC) at idle is not adjustable & it reliant upon the max being correctly set. To adjust; (a) Disconnect the link rod which move the base of the magneto. With the engine running (test tank but on the boat is half OK) Move (adjust) the stop as appropriate till the max timing is right with the magneto based turned against the stop, tighten the stop. Be careful & safe. (iii) To adjust the sych, (engine off) turn the throttle to WOT & make sure the throttle lever on the carb is just against it's stop, if not adjust till it is (locknut on the tight cable?) Leaving the throttle at WOT rotate the magneto base plate till it rests against the max advance stop, then adjust the length of the link rod so it will clip onto the carb linkage without changing the timing setup. Turn the throttle to slow, & make sure the starter limiter is still preventing start at more then slow. If not; adjust. Apologies again for not having the 77 stuff but this might help if you don't do better elsewhere K |
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