74 Evinrude Yachtwin

[cloudsnme]

Hi, I am new to these forums but need some help with a 1974 Yachtwin 4HP I bought last year. The lower unit gets a lot of water in it after a day of fishing. I removed the unit but can't see any seal in the shaft from the powerhead. Do you fill the lower unit with a water proof grease or what.
Thanks

 

[samo_ott]

Re: 74 Evinrude Yachtwin

The way to know for sure is to pressure test the LU. There are several seals there. One is below the water pump. One behind the prop. One on the shifter rod if you have a shifter on it.

Have you ever change you LU oil? And it is LU oil, not grease (grease was used in the 40's or so!) Did you replace the washers on the screws if so? Try that first as that is the easy fix.

 

[F_R]

Re: 74 Evinrude Yachtwin

Hi, I am new to these forums but need some help with a 1974 Yachtwin 4HP I bought last year. The lower unit gets a lot of water in it after a day of fishing. I removed the unit but can't see any seal in the shaft from the powerhead. Do you fill the lower unit with a water proof grease or what.
Thanks

If you are getting a "lot" of water after only one day, you have a major leak. You don't see any seal?? Did you remove the water pump and look? The seal is below the pump impeller. Drive shaft and prop shaft seals are alike and are part number 300599, superceded by 327031, (or 18-2035 here at iboats)

Did you look behind the propeller? Monofilament fishing line wrapped around the shaft is a famous seal killer.

 

[cloudsnme]

Re: 74 Evinrude Yachtwin

Ok thanks , I will pull the unit apart again. Where can I get seals for this unit?

 

[samo_ott]

Re: 74 Evinrude Yachtwin

Any OMC dealer, lots of after market places... Right here at iBoats I believe.

 

[F_R]

Re: 74 Evinrude Yachtwin

http://www.iboats.com/mall/partfind...&gd_poid=110198&gd_row=4&**********=370023462

 

[cloudsnme]

Re: 74 Evinrude Yachtwin

The way to know for sure is to pressure test the LU. There are several seals there. One is below the water pump. One behind the prop. One on the shifter rod if you have a shifter on it.

Have you ever change you LU oil? And it is LU oil, not grease (grease was used in the 40's or so!) Did you replace the washers on the screws if so? Try that first as that is the easy fix.

Thanks for all the help. I have another question. Which way do the water pump impeller fins bend. Toward the rotation or away?

 

[Vic.S]

Re: 74 Evinrude Yachtwin

gear case diagram. HERE

seals are #4 and # 10 part no 300599. Assuming the 90? drive not a weedless one.

Also renew O ring #2 and the seal on the oil drain plug #9

looking from above rotate the impeller clockwise as you ease it into position so that the vanes trail backwards.

 

[cloudsnme]

Re: 74 Evinrude Yachtwin

Thanks very much. I am getting to know this little beaut. I hate to be a pain but I have one more question.
I put new points and plugs in this outboard but when you idle it right down the bottom cylinder cuts out after a few minutes.
I thought it was fouling up with fuel but it appears to be starving for fuel. If I pull the choke out quickly it fires up again. I have to get a new primer bulb as this one is not holding the prime. Could that be the problem?
I am going to clean the carb and do the LU plus whatever else it needs.
It is just the right size engine as it fits in the hatch on the float of the seaplane.

 

[Rick.]

Re: 74 Evinrude Yachtwin

Did you say seaplane? Must be nice.

Your motor weight is very close to 35 lbs. maybe a couple more lbs. due to the long shaft. Gas and tank must be added.

I would recommend you do a carb. kit, as you said. It just makes things run so much better and eliminates a great deal of potential trouble. Take every precaution to make sure you clean it very well. I soak mine then use a spray carb. cleaner and make sure I get every orifice from both directions and then blow it out with compressed air. I would also recommend all new gas lines at the same time. If it idles better with a little bit of choke I would recommend turning you slow speed needle a bit richer. Turn it counter clockwise 1/8 increments until it idles smoother. If your doing a carb. kit you"ll have to reset the needles so you may not want to bother at this point. The primer bulb will not stay hard when the motor is running. It isn't supposed to. Without the motor running you should be able to pump it until it is firm and it should stay that way for a few minutes or until you fire the engine. After the engine is fired the primer bulb really becomes not much more than a gas line which is under sucktion at that point. You say the bottom cylinder cuts out. How did you make that determination? If it is in fact loosing spark, then you probably have a bad coil. If your coils are cracked you should just replace them both but a lot of fellows report coils cutting out after they get warm which is when you say your loosing the bottom cylinder. I would also consider replacing your plug wires when you do the coils. Your motor is 35 years old and if you want it to run nice for an extended period it deserves some new parts by now. I just went through my (new to me) 71 - 4HP over the winter and she's running like a champ. They are great little motors. Best of luck. Rick.
One more thing.
http://shop2.evinrude.com/ext/index.aspx?s1=1f0d3cd2c4dce396f18c8c19e0b85531

 

[cloudsnme]

Re: 74 Evinrude Yachtwin

Thank you very much for all the info including the parts source. I got this motor very reasonable. I don't think it has much time on it but it lacked maintenance. It is the short shaft model. Yeah I realized a dream I never thought possible a few years ago. I have been flying for 32 years but until 5 years ago it was all wheels. A once in a lifetime opportunity came up 5 years ago and we bought a Cessna 182 from a fellow in Firnie BC. Then had it converted to floats. I would never go back to wheels again. I fly Northern Manitoba and needed a small motor to carry around as there are a few small boats at different locations.
Thanks once again.
Wally

 

[samo_ott]

Re: 74 Evinrude Yachtwin

It's a short shaft? A Yachtwin? Huh. I thought they were all longshafts for auxilary's for sailboats. See, you learn something every day!

 

[Rick.]

Re: 74 Evinrude Yachtwin

Wally: I thought Yachtwins are supposed to be long shaft not short. I wonder if it just has a Yachtwin cowl on it. Who knows. Everyday I learn something new on this site. If it's a short shaft it is 35lbs. for sure. I've been to Fernie (2 Hrs. DRIVE) many times (excellent cutthroatfishing on the Elk River) and even went fishing up the Hansens Lake Road once which they said would eventually get you to Flin Flon Manitoba. We fished at Lake DeChombeu (sp) and a bunch of others in that area. Enjoy your motor. They won't get you anywhere fast but they will get you there eventually. Rick.

 

[cloudsnme]

Re: 74 Evinrude Yachtwin

From looking up parts I see there are two different model numbers for this 1974 Yachtwin. The other model number could be a long shaft.
I now have another question. I also have an Evinrude 9.9. I think I bought it in the eightys but I am not sure. I looked for my model year but it is not there.
There are dozens but for some reason mine is not listed. The model number is:
10RCGC. Serial number is R13o3155. Everything works good but I am thinking it is time for some maintenance like carb overhaul....impeller and so on.
I am no outboard expert so I am not sure what all should be done.

Wally

 

[Rick.]

Re: 74 Evinrude Yachtwin

You should start a new thread for the new motor. Look at the top of this forum and you will see "Top Secret Stuff". It really isn't a secret but just packed with good information including steps for maintaining motors and getting them ready to start after a few years of rest. Your engine numbers are not working. C is 8 which means eighty something but there is no G following C. The last C is just a rev. of production and usually not important. R means rope start. Take a better look and start a new thread. Best of luck. Rick.

 

[cloudsnme]

Re: 74 Evinrude Yachtwin

Thanks for all your help Rick. Yeah I will recheck the numbers on the 9.9 and start a new thread.
Wally