New Yamaha 115 4-stroke

C

captbob

Cadet
Joined
Jun 1, 2003
Messages
8
I just purchased a new Yamaha 115 4-sk. I have finished the break-in period and want to know what is the recommended operating rpm for this engine? It tops at 6000 which is more than my last 2-sk. 115 which was around 5200 (different hull). Does this mean this engine operates at a little higher rpm at most speeds? I have been told that Yamaha governs their engines so that they do not reach their max. so people will not blow them up running them WOT. Is the 4-sk. the same and does a 4-sk. have a lower/higher tolerance to continuous operation at near max. rpm than a 2-sk.? I have also heard that HPDI motors don’t do well when you add a remote fuel/water separator because of the high pressures they use and the potential for problems maintaining the constant pressure. Does that hold true for this motor?<br />Thanks for expertise. :)
 
JB

JB

Honorary Moderator Emeritus
Joined
Mar 25, 2001
Messages
45,907
Re: New Yamaha 115 4-stroke

Are you telling us that you bought a new Yamaha and didn't get an Owner's Manual with it??<br /><br />Go to the dealer and get it. You need it.<br /><br />Good luck. :)
 
B

bossee

Senior Chief Petty Officer
Joined
Jul 18, 2002
Messages
727
Re: New Yamaha 115 4-stroke

I just purchased a new Yamaha 115 4-sk.<br />----------<br />Hi,<br />A 2003 Yamaha F115 then I assume?<br /><br />---------------<br />I have finished the break-in period and want to know what is the recommended operating rpm for this engine? It tops at 6000 which is more than my last 2-sk. 115 which was around 5200 (different hull). <br />---------------<br /><br />Have a look in the manual.<br />It is here (US, english, 2003, F115):<br /> http://www.yamaha-motor.com/service/manuals/2003/lit-18626-05-10_403.pdf <br /><br />--------------<br />Does this mean this engine operates at a little higher rpm at most speeds? <br />--------------<br />No, not neccessarily. Recommended max operating rpm is as You can see in the manual 5000-6000 rpm, maximum output at 5500 rpm.<br />Idle 700-800 rpm. If You think your max rpm is a little high you can change propeller to a higher pitch, example: if you have 13x19 now you can go 13x21 (and as a rule of thump the rpm drop will be around 200 rpm for every higher pitch) and you should then get an rpm at about 5600 rpm. The boat will have sligtly slower accelaration then but top speed might be 1-2 knots more. <br /><br />-----------<br />I have been told that Yamaha governs their engines so that they do not reach their max. so people will not blow them up running them WOT. <br />-----------<br />I do not know. I have a Yamaha F115 (2003) and at full throttle it reach 5900 rpm with a Yamaha Black SS(Stainless Steel) prop 13x19-K and top speed 39 knots with my boat (a Yamarin 5820).<br /><br />------------<br />Is the 4-sk. the same and does a 4-sk. have a lower/higher tolerance to continuous operation at near max. rpm than a 2-sk.? <br />------------<br />As long as You are within manufacturer rpm range it should be OK.<br /><br />------------<br />I have also heard that HPDI motors don’t do well when you add a remote fuel/water separator because of the high pressures they use and the potential for problems maintaining the constant pressure. Does that hold true for this motor?<br />-----------<br />No, I have a water separator fuel filter, I use a standard one (not Deluxe):<br /> http://www.yamaha-motor.com/accessories/otb/fuel01.html <br />You can read on this page why the water separator fuel filter must be correct size and maintanied properly.<br /><br />Good luck with your new outboard.<br /><br />/Bo
 
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