Air Cooled Outboard

[Drowned Rat]

Anybody have some ideas on how to help air cooled outboards run cooler. I live in Arizona where 120F is normal in the Summer. Do Synthetic oils help? How about Synthetic Gear oil? Any help would be appreciated. I notice that they don't sell full synthetic 80W 90 gear oil here. Is there a reason? They do have 75W 90 though. What would happen if you put 75W 90 in a lower unit that calls for 80 W90?

 

[crazy charlie]

Re: Air Cooled Outboard

All synthetics are great,I dont think it will help run cooler.Make sure it gets as much air as possible without any restrictions.Maybe add a scoop to the cover.Charlie

 

[JB]

Re: Air Cooled Outboard

Air cooled 2 strokes will always run hotter if you use TC-W3 outboard oil, DR. The W is for water cooled.<br /><br />Use a premium grade chainsaw oil, and be sure that the mix is what is recommended by the manufacturer. Most air cooled 2 strokes run more oil than water cooled. 16:1 is not uncommon.<br /><br />Good luck.

 

[cobra 3.0]

Re: Air Cooled Outboard

JB, I think Drowned Rat is talking about his 5hp Briggs and Straton 4 stroke. I'd be more worried about the engine oil than the gear oil in that heat. <br /><br />Check out what the manufacturer recommends for than kind of extreme heat situation. Thicker oils will be a must.

 

[JB]

Re: Air Cooled Outboard

Thanks, Cobra.<br /><br />Sure is easy to look stupid when you've been denied critical info.

 

[sloopy]

Re: Air Cooled Outboard

why are you worried about the lower unit temperature?!?! Unless the water you boat in is 200 deg, you should not have to worry about different oils in the lower unit. Any outboard lower unit oil will work in the Briggs and Stratton outboard. For the engine; amsiol synthetic MIGHT make the BS run better in hot temperatures, if it is really hot use a heavier weight oil.

 

[BillP]

Re: Air Cooled Outboard

Be cautious about using a viscosity higher than the motor mfg recommends...especially on air cooled engines. <br /><br />Several years ago one of the motorcyle mags did a series of oil temp tests on aircooled mcy engines. They used a dyno and found heavier oil made the engines run hotter. One of the comparisons was between 10w-30w and 20w-50w oil. The 20-50 made the engines run at the high end of acceptable temps. Moral of the story was to stay within mfgs specs for normal operation.