Can I rebuild the carburator on an old Evenrude 65 hp O/B?

[CatFisher]

Hello again everyone!

I have ordered an original 1972 OMC repair manual for my motor from an eBay vendor, but it has yet to arrive I'm really hoping to take at least a test run of the boat in this weekend, weather permitting. Could someone help me understand what I have to do to set the low speed idle and mixture on my motor, please? Do I need a tachometer to perform this procedure?

Thanks very much for your help!

-CatFisher

[rolmops]

You do not need a tachometer for that one.

It is best to do in open water.

Close the needle all the way.(hand not quite tight). Turn it back open about 1 1/2 turns. Start the engine and let it run a bit.Now lower the RPMs as much as you can without killing the engine.

Slowly close the needle,the RPMs should go up.Keep on closing until the engine starts sneezing,now turn it back open a quarter turn and you are done. You should be at about 800 rpm.

If you do this on a hose or in a barrel you will get different results because the water pressure on the exhaust gases is not high enough.

If you decide to do this in a barrel,make sure that the water level in the barrel is higher than your water pump.

[CatFisher]

Hello, rolmops!

Thanks again for your help! I have been running on the hose for now, but I could try to get it in the water for this adjustment if I really have to. So, am I just turning the slow speed needle coming out of each carb? Do I just repeat the procedure one at a time for each carb needle? And is that the only adjustment I need to do? Is there something else about an idle mixture screw as well, or not for this motor? I also have some kind of mixture knob on the front of the motor. The linkage to this knob was disconnected by the mechanic when I picked the boat up. I still have this disconnected since I'm not sure where it connects or exactly what it does (my manual is expected Monday). But I think that's OK for now, isn't it?

As a point of interest, I performed my own compression test today after letting the motor run for about 20 minutes. My results were 119 psi on the first, 116 psi on the second, and 118 psi on the third. I'm thinking that's pretty good for this old motor, any thoughts?

Thanks a lot for your help, rolmops!

-CatFisher

[LongLine]

An important thing with compression is that they're all close. Getting 100-teens is very good for that engine.

Tom B.

(LongLine)

[CatFisher]

An important thing with compression is that they're all close. Getting 100-teens is very good for that engine.

Tom B.

(LongLine)

Thank you, LongLine, that's just what I thought

-CatFisher

[rolmops]

Yes,that is very good compression.

sorry for just serving you the generic low idle adjustment .I somehow forgot that this is 3 carbs and not one like on my 1957 35 horse engines.

The process remains the same,but you will have to try and play the same trick on all three and set them roughly the same.Just remember that too lean a setting is not very good for the engine at all.It is safer to err on the rich side. As for mixing oil.This engine is a 1:50 but 1:40 is not terrible, 1:60 can kill it. My favorite fuel stabilizer is "Seafoam". This is not only a stabilizer, but also a carburetor cleaner and it decarbs the cylinders. I dump half a pint in every third tank and of course in the fuel that is left in the tank in winter. In 12 years on my 1957 35 horse Johnson I have yet to have trouble starting up in spring with fuel that has been in the tank all winter.

Your lower unit takes special oil and not the regular lower unit oil.This is because you have an electric shift system that requires slightly different oil,or it will simply not shift.

good luck!

[L&M]

Your lower unit takes special oil and not the regular lower unit oil.This is because you have an electric shift system that requires slightly different oil,or it will simply not shift.

That would be: OMC Premium Blend or the equivalent Type C fluid.

[CatFisher]

...Now lower the RPMs as much as you can without killing the engine.

What do you mean by this? Lower the RPM's by pulling the throttle back, or is there some other adjustment I make on the motor or remote control?

I think I'm going to try and get it close in a large garbage pail, and if that works I can try to bring it to the water this weekend.

Thank you very much for your time, I really appreciate it!

-CatFisher

[dcso]

if possible ask for a sea trial. I had carbs rebulilt and still had had the same problem even after chainging out all the old fuel lines, 800 billls later I was out after trying to remide the problrem. Now i own an IO. I don't think its unreasonable to ask to to have the mechanic that repaired it to run an on open water test as opposed to in a tank! trial tanks are not open water

my thoughts

ted

[rolmops]

You should use your remote control and go as low as you can without shutting off the engine. This is to make sure that your idle is at the lowest possible point to start with. After you have set the idle with the engine in neutral you want to go for a ride and finalize the adjustment while the engine is under a load.That way you fine tune the whole thing

[CatFisher]

if possible ask for a sea trial. I had carbs rebulilt and still had had the same problem even after chainging out all the old fuel lines, 800 billls later I was out after trying to remide the problrem. Now i own an IO. I don't think its unreasonable to ask to to have the mechanic that repaired it to run an on open water test as opposed to in a tank! trial tanks are not open water

my thoughts

ted

Great thought, dcso, but unfortunately I'm the "mechanic" that rebuilt the carbs I think I'm going to try and get it in the water tomorrow (Friday) afternoon or evening. Hopefully I can get the carbs tuned and going without much trouble.

Thanks for your input, I definitely appreciate the help!

-CatFisher

[CatFisher]

Your lower unit takes special oil and not the regular lower unit oil.This is because you have an electric shift system that requires slightly different oil,or it will simply not shift.

That would be: OMC Premium Blend or the equivalent Type C fluid.

Thank you, L&M, that is what the mechanic used in the lower unit this Spring, and what I will continue to use in the future. I understand this "selectric" shift can be problematic and potentially expensive to fix. I'm sure it's best to keep running the good gear oil in the hopes of minimising any problems.

Thanks again for your help!

-CatFisher

[CatFisher]

You should use your remote control and go as low as you can without shutting off the engine. This is to make sure that your idle is at the lowest possible point to start with. After you have set the idle with the engine in neutral you want to go for a ride and finalize the adjustment while the engine is under a load.That way you fine tune the whole thing

As always, thanks for your time and help! I think I have the idea, and if nothing else my repair manual is *supposed* to be here Monday. I'm anxious to run the motor under load, so I am going to try and get it to the water tomorrow (Friday), if I can.

I do have one more question for now: There is a sticker on the motor's air intake that says to adjust the idle from the remote control. Where do I find this adjustment? Do I need to take the cover plate off the remote control? The only other adjust I find at the remote is the throttle friction, which is different.

Oh, I guess two more questions; do I need to adjust the throttle linkage, and if so, how?

Thanks a lot, rolmops, your help has been invaluable!

-CatFisher

[rolmops]

http://www.ishopmarine.com/ishop/jsp/As ... 100-005-EJ