1980 5M - Is it air cooled?

[guy48065]

I've only used this 5hp motor a couple times in 10 years but had it out last weekend. Can't find a telltale so I was watching it closely but it ran for hours without an issue.
Part of my confusion comes from seeing an impeller available for this model. There's an intake tube positioned to get some prop wash pressure. I don't understand a pump with no "pisser".

My previous boat had a 40hp Mariner that looked like it's big brother--and it certainly had the pisser.

 

[GA_Boater]

Not all motors have tell-tells.

 

[jimmbo]

A lot of water cooled engines didn't have a 'Pisser'. Mariner Brochure says Water Cooled with Thermostat

 

[Scott Danforth]

tell tales came about in about the 70's

motors from the 20's to the 70's survived without the tell tale by simply having the folks do maintenance.

your 1980 may have a tel-tale at the back of the cowling, however the plastic "nozzle" may be plugged . however all the small 3hp to 9.8hp motors in 1980 had a water pump. you do have to measure the drive shaft diameter as there are two diameters available.

 

[flyingscott]

I bet you have a Yamaha built Mariner. Put up a pic or model/serial #

 

[guy48065]

Yes it's a Yamaha. Data plate sez 5M 661S 034994

I don't know how much help that is--given the strange serializing they used then. The guide here was inconclusive & a thread I started years ago gave conflicting answers.

When I Google that model number I see many results that refer to it being air-cooled, and is why I'm asking here.

 

[guy48065]

I guess I don't have a picture. It looks identical to this:
https://youtu.be/ywJQe1cjBdo

 

[Mohawkmtrs]

Take the air shroud off to access the cylinder and head...if they have cooling fins similar to a lawnmower engine then it's air cooled.

By the way, the serial # you posted (5M 661S 034994) is a 1976 model year (Serial # Range 26311 - 38303).

The impeller may be used to cool the exhaust only...there may be a tell-tale hole located at the top of the driveshaft housing.

 

[jimmbo]

By the way, the serial # you posted (5M 661S 034994) is a 1976 model year (Serial # Range 26311 - 38303)

Well that bit of info could certainly affect the Accuracy of info/advice regarding the motor.

 

[guy48065]

Well that bit of info could certainly affect the Accuracy of info/advice regarding the motor.

I was using info from my 11-year old inquiry here:

https://forums.iboats.com/forum/eng...riner-outboards/283248-need-yom-on-mariner-5m

 

[jimmbo]

You already had Knowledge that the Model Year was sketchy, it would have been nice if you had included that little Tidbit, as there is a great deal of difference between a 1976 5 hp and a 1980 5 hp

 

[guy48065]

Hi jimmbo,

To settle the question of whether mine is a 76, as determined above, or an 80 as the seller claimed--what are some of the great differences?
Those tidbits are useful to me.

 

[jimmbo]

If your engine is air cooled it's going to have a shroud to direct the airflow, similar to what a Lawn Mower or Garden Tiller would have. This would be under any cosmetic engine cover/cowl. There would also be an area on the cowling to let cooling air in and out. Air cooled engines are noisier than liquid cooled engines. They also run hotter, and require different 2 stroke oil than liquid cooled engines. Air cooled engines often do have a small water pump, to inject a bit of water into the exhaust housing to keep it from getting too hot and melting any plastics and rubber materials

Sellers often either have no clue what year an engine is, some even try to say it newer than it lies to get a higher price. Mercury Outboards are often 10 or 15 yrs older than their advertised year. It is important to have the model and serial numbers when ordering any parts, especially with the Brunswick engines, Mercury and Mariner

 

[guy48065]

Thank you. I think we've nailed the air vs water cooling question. I'd like to know more about those differences you teased about 76 vs 80.

I certainly don't want to be one of these "clueless" sellers when correct info is so readily available.

 

[jimmbo]

One is air cooled, the other water cooled. I doubt the remainder of the motor is the same either. Go to a dealer and ask if you can look at the parts catalogs for each engine.

 

[guy48065]

You're a "20 Questions Master Baiter"

Ok I'll take the bait. WHICH?
and
Are they both model 661, made by Yamaha for Mariner?

I'm not the only one confused with conflicting information:
https://forums.iboats.com/forum/eng...outboards/460322-what-year-is-my-mariner-5-hp

 

[jimmbo]

http://www.autorepairmanuals.biz/page/608055

5 M

661-26311 - 661-38030

1976