Hi guys, I'm going to look at a Yamaha 15hp 2 stroke this week - currently running a 9.8 Tohatsu which I'm very familiar with but not the Yams. Any tips please on viewing?
Just to confirm the 'S' on the label makes it a short leg? And the year is '99? Was this the last model of the 2 stroke 15's or was there a later one? Was the cowling colour and graphics always the same?
Yep, that was the last model of Yamaha 2 stroke. Colours are still current (Blueish Grey Metallic ). Fantastic engine, ran the 9.9hp version on a Zodiac SR310, at 37kg its light for a 15hp and the gear shift on the tiller is a nice touch.
No known problems, just check the usual, tell tail, prop damage etc.
Thanks for that. And double checking this is the short shaft?
Anyone else chip in any tips for maintainance, or link to a workshop manual etc please?
try ebay for CD manual, only a few £££, but check that it covers your engine, I have one of the CD manuals which does not have my exact model ( going by the letters after the hp ) but its is still useful.
Any other Yam owners confirm the best oil ratio to use? I believe the manual states 100:1 wheras my Tohatsu is 50:1. Is there a case for running the Yam 50:1? Is this recommended anyway for commercial use?
Any other Yam owners confirm the best oil ratio to use? I believe the manual states 100:1 wheras my Tohatsu is 50:1. Is there a case for running the Yam 50:1? Is this recommended anyway for commercial use?
My 1997, 75 Yam commercial is 50:1.
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Any other Yam owners confirm the best oil ratio to use? I believe the manual states 100:1 wheras my Tohatsu is 50:1. Is there a case for running the Yam 50:1? Is this recommended anyway for commercial use?
I run mine on 100.1 never had a problem sweet little engines love mine wife & kids are happy to use it too!
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Thanks Nick, you've had more than a few engines I guess - is there any disadvantage to running on 100:1 - cost is negligable but is it a case of more oil is better or worse. Not that I'm cynical but maybe Yamaha quote 100:1 to give perceived lower running costs/less emissions etc. If commercial users are advised 50:1 there must be a reason (less wear?).
Thanks Nick, you've had more than a few engines I guess - is there any disadvantage to running on 100:1 - cost is negligable but is it a case of more oil is better or worse. Not that I'm cynical but maybe Yamaha quote 100:1 to give perceived lower running costs/less emissions etc. If commercial users are advised 50:1 there must be a reason (less wear?).
As far as I know increasing the oil ratio will just foul up the plugs, I just stick to that is recommended!
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Folks are always going to have different opinions on this Max. My Mariner 15 says 100:1 private use and 50:1 commercial use. There must be some advantage to 50:1 for heavier use or they wouldn't advise it. So I run at 75:1. Keeps me happy and never foul the plugs, even on the river at 5mph which is not far off tickover for hours at a time.
Having said that the Yamaha handbook you linked doesn't mention commercial use so perhaps they reckon they've cracked it at 100:1 for all useage types.
BTW noted the running in is at 25:1 for 10hrs with no mention of different plugs so I guess they will cope with more oily fuel if you want.
Have run these engines for years and never had problems with them. They are so much lighter and better suited to small boats than their modern 4 stroke replacements and as long as you don't run at full power a lot they are almost as economical.
Never gas any major problems with them having used 10 of them over the years for work apart from a spring going on one of the gear selectors. Easy enough to replace and only £4 for the part.
Always run them at 100:1. Adding more oil does nothing but produce more smoke and clog up spark plugs.
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