1972 Evinrude 50 HP "Lark". Need start procedure and a couple of questions

[eavega]

I've recently acquired a boat with a model 50273C outboard. This motor has a hydroelectric shift, a key start, a toggle switch, and a throttle stick. I know the start procedure for the smaller, manual shift, pull start motors, but I'm not quite sure what the start procedures are for this motor. I have the service book, which is a wealth of knowledge for troubleshooting and maintenance but not so helpful when it comes to normal operation.
Also, I was advised in a previous thread that this motor might not like to run on muffs, but I see that it has bigger water intakes on either side of the leg, which would lead me to believe I could at least do preliminary checking on this motor if I get the square muffs. Any opinions?
Lastly, I can't see if this motor has a 'pee hole' anywhere. Given that the water discharge is below the pump, and therefore underwater when the motor is running, I would assume that there has to be a tell-tale somewhere to verify that water is circulating. Can anyone tell me if there is, in fact, a pee-hole or other method of determining whether water is circulating (other than the motor overheating or not).

Thanks

Eric

 

[tashasdaddy]

Re: 1972 Evinrude 50 HP "Lark". Need start procedure and a couple of questions

Re: 1972 Evinrude 50 HP "Lark". Need start procedure and a couple of questions

Start peocedures in TOP SECRET FILE > http://forums.iboats.com/showthread.php?t=299680

tale tell, is the exhaust relief ports on the back midsection of the leg. you should get mist or droplets, on muffs.

 

[freddyray21]

Re: 1972 Evinrude 50 HP "Lark". Need start procedure and a couple of questions

Re: 1972 Evinrude 50 HP "Lark". Need start procedure and a couple of questions

the toggle switch is the choke. it probably has a small lever on the side that is your warm up lever. turn the warm up lever up. flip the toggle to engage the choke and turn the key. once it fires let go of the toggle switch. this is assuming you have primed the motor.

 

[jay_merrill]

Re: 1972 Evinrude 50 HP "Lark". Need start procedure and a couple of questions

Re: 1972 Evinrude 50 HP "Lark". Need start procedure and a couple of questions

See above for the starting procedure. I'll add to that comment that your motor has an automatic, thermally operated choke function too. There is a sensor on the port side of the cylinder head, which energizes one of the coils in the choke solenoid, whenever the key is moved to the "on" position and the temp of the head is below a certain value.

Yours may or may not be hooked up, as there was a Service Bulletin recommending that it be disconnected. The reason for the SB is that the thermal choke tends to cause the engine to run rich from being choked when it doesn't need to be.

Your engine should run fine on the muffs. The disadvantage of running on muffs has more to do with troubleshooting and/or servicing the motor. Since there is no back pressure on the exhaust when the engine is not submerged in water, it will run more "freely." It may appear to idle well, but then stall at idle when in the water. You also can not set the timing on the motor properly, because this is normally done in gear with resistance (from the water) on the prop or test wheel.

Your motor does not have a "tell tale." When you run it on the muffs, watch the vertical slits in the gearbox for water discharge. You won't see water coming out for a minute or so, until the thermostat opens up. You may also see water and/or mist coming from the two relief outlets on the backside of the engine's midsection.

There is a thread here at iboats regarding installation of a tell tale on OMC motors that don't have them. Be careful of the SB on this issue, however, because the positioning of the discharge nipple shown in it, may not be applicable for your motor.

Although some people don't seem to care for my choice of location, I installed a discharge nipple in the head of my 1972 Johnson 65hp motor. I made my location choice in consultation with my local OMC/BRP dealer. The specific mechanics who advised me all have many years (up to 30) as OMC service technicians. I chose to offset the nipple from center, in order to avoid interference with the lifting eye on the motor.

The nipple that I used is a stock OMC/BRP carburetor part. Once again, some have negative opinions about using a bronze nipple in an aluminum head, due to the possibilty of dissimilar metal corrosion, but I was also advised that this should not be much of an issue.

Tell Tale Installation Link

http://forums.iboats.com/showthread.php?t=222677


My Installation Photos

SB Re Thermal Choke