My carbed Yamaha 40 HP Four Stroke says to use 10w30 or 10w40 oil. There is no mention of FC-W rating because the motor was built in 2003. I've run Rotella 5w40 in her for a season but want to run synthetic. How do you think SynPower 10w30 will hold up. I generally run the boat at 4600 RPM for about 10 minutes to get to the crabbing grounds and they it idles in gear for 3 to 6 hours sometimes before heading home. I feel a quality group III or better would work for this situation. What do you guys think?
SynPower for Yamaha F-40
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Rotella 5w40 should be synthetic.........
I would also need to know how often this use is done, and how often you would like to or can change oil. A carb idling that long=fuel dilution, to me. If dino Rotella ok, why not try syn Rotella? Thicker is allowed, and you used 40wt. before, so why do you want to drop to 30wt.? Lesser oil changed more often may equal or exceed greater oil used longer, especially in this case.
Originally Posted By: jldcol
I would also need to know how often this use is done, and how often you would like to or can change oil. A carb idling that long=fuel dilution, to me. If dino Rotella ok, why not try syn Rotella? Thicker is allowed, and you used 40wt. before, so why do you want to drop to 30wt.? Lesser oil changed more often may equal or exceed greater oil used longer, especially in this case.
I will change my oil every 50 hours because of all of the idling. My manual says to use either a 30w or 40w so both are acceptable. I was thinking that a 30w. syn would be pretty stout. I can go to a 40w syn Rotella. I only need 2 quarts and can use the SynPower I bought for my Tacoma. If the manual states a 10w30 or 10w40 dino, wouldn't a 10w30 synthetic preform better??
I would also need to know how often this use is done, and how often you would like to or can change oil. A carb idling that long=fuel dilution, to me. If dino Rotella ok, why not try syn Rotella? Thicker is allowed, and you used 40wt. before, so why do you want to drop to 30wt.? Lesser oil changed more often may equal or exceed greater oil used longer, especially in this case.
I will change my oil every 50 hours because of all of the idling. My manual says to use either a 30w or 40w so both are acceptable. I was thinking that a 30w. syn would be pretty stout. I can go to a 40w syn Rotella. I only need 2 quarts and can use the SynPower I bought for my Tacoma. If the manual states a 10w30 or 10w40 dino, wouldn't a 10w30 synthetic preform better??
The 30 is better mpg wise, maybe, and the 40 better at the fuel dilution. If have a use for mass quanties, for other engines, no harm in trying. If change that often can get a quick sense and change if/as needed. You mean 2 gals for Tacoma, leaves 2qts. for the boat?
Originally Posted By: jldcol
The 30 is better mpg wise, maybe, and the 40 better at the fuel dilution. If have a use for mass quanties, for other engines, no harm in trying. If change that often can get a quick sense and change if/as needed. You mean 2 gals for Tacoma, leaves 2qts. for the boat?
I have a stash of oil for my Tacoma and can add the 2 quarts to my stash for later use. As for the Yamaha, I'm going to use the SynPower for 50 hours and see how it does. I just want to protect the little 40hp since it's been good to me for the last 350 hours. I've used a wide range of oils for that time and have always changed it out 2 or 3 times a season depending on how many hours and time I'm on the water.
The 30 is better mpg wise, maybe, and the 40 better at the fuel dilution. If have a use for mass quanties, for other engines, no harm in trying. If change that often can get a quick sense and change if/as needed. You mean 2 gals for Tacoma, leaves 2qts. for the boat?
I have a stash of oil for my Tacoma and can add the 2 quarts to my stash for later use. As for the Yamaha, I'm going to use the SynPower for 50 hours and see how it does. I just want to protect the little 40hp since it's been good to me for the last 350 hours. I've used a wide range of oils for that time and have always changed it out 2 or 3 times a season depending on how many hours and time I'm on the water.
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