1972 40hp Johnson

[MichaelMullis]

Does my Motor have an alternater? I do not see anything that looks like it might be a alternater. This is a electric start motor that has the pull cord also. I just got this motor on a 17' toon this weekend. I also found a hole in the extension section on the lower unit, this is a long shaft, about the size of a dime, will this cause any problems? I tried to start motor yesterday but no fire on either plug so I guess I will be putting a tune up kit in it next. How is the reputation of these motors? I got this motor, 17' MonArk toon,both 1972, and a 1999 Wesco trailer ( will carry up to 20/22') for 1000.00 so I figure I can afford to put a little money into restoring. I am already redecking the toon. Any input from all would be helpfull. <br />Thanks<br />Michael

 

[Barnacle_Bill]

Re: 1972 40hp Johnson

You have an alternator per se, but its called a stator which is under the flywheel. It provides AC power to the motor through a rectifier. The simplest way to see if it is working is to check the voltage at the battery with the motor off. Then check it again with it running. It should be higher.

 

[Namcali]

Re: 1972 40hp Johnson

Bait,<br /><br />I believe your motor has the "generator" not the alternator. If you look closely on the oposite side of the starter, you will be able to see it if it's there. <br /><br />About the hole, if I image correctly what you are talking about, it's normal since there is a little crack hole in the lower unit. I highly recommend you change the lower unit oil. If the oil look milky, there is water on it...so it must be fixed.<br /><br />It sounds like a good deal for the boat, motor, and the trailer.<br /><br />Good luck,<br /><br />Nam

 

[Paul Moir]

Re: 1972 40hp Johnson

The dime-sized hole is an exhaust relief hole - no big deal there.<br />I'm pretty sure the alternator IBNFISHN is refering to didn't come out on the 40hp until 1974, and if your engine was equipped with a charging system, it would be the generator Nam is talking about. It's connected to the flywheel by a belt.<br />Since you have no spark, try disconnecting and isolating the two black wires that come from the plate that turns with the throttle up underneath the flywheel. That will disable all the saftey switches and cutout switches on the engine. If you still have no spark, you'll need to pull the flywheel and figure out what parts you'll need. You must use a puller that operates on the three screw holes in the center of the flywheel - edge pullers will destroy the flywheel.<br />Once you have it off, inspect the flywheel key, the points and the coils. If the coils are all cracked, they must be replaced as well. Fortunetly, replacements are inexpensive.<br />Naturally, a service manual is manditory.<br />Good luck!

 

[Barnacle_Bill]

Re: 1972 40hp Johnson

How about that. I assumed (I gotta quit that) that it would be the same as a 72 85HP I used to have.