I have a strange leak on my 1972 Evinrude 25 (model 25252R). I have replaced the crankshaft seal, replaced all the fuel hoses, and sealed up the bypass cover gaskets. Fuel seems to be finding its way all over the motor, but a major concentration near the carbuerator. I have made sure the float is adjusted properly and the needle valve is in fact shutting off the fuel supply when the float is closed. The only thing I can think of is fuel is coming back out through the carb. Anyone have any ideas what I can do to remedy this? The motor is quite young, when I acquired it, it had less than 25 hours on it and looks like new. This is the 2nd carb i've had on the motor, too.
Pull your carb and get a flashlight and shine it back in the reed valves and see if there is a bolt or something lying in there. It wil be easily seen.
A bolt, you mean just lying around in the bottom of the plate that covers the reeds? Or an actual bolt in the reed plates, or one that should be in the reed plates that isn't?
No bolts laying around. Replaced both gaskets, and checked the reeds. Local outboard mechanic said they were in A1 condition. So I reassmebled. Don't think its leaking fuel any more out the carbuerator. But at midrange, around half throttle, it has a skip in it. If you let it be for a few seconds it works itself out of it.
I wonder if I shold be using 89 or 91 octane fuel instead of 87? Does the kind of oil used make a difference? Should I use Johnson/Evinrude TCW3 oil or is the Havoline oil fine?
Set throttle to idle (engine off & in gear). Exaggerate the motion of the throttle butterfly shaft on the carburetor by attaching a piece of stiff wire. Open the throttle slowly until the wire *just* begins to move. At that point, the roller that follows the cam on the armature plate (the part the coils mount to) should be right between the two marks on it. If it is not midway between the two marks, loosen the linkage clamp on the throttle butterfly shaft and adjust it slightly.
If that's not it, then has the carburetor been rebuilt? How do the spark plugs look? (black/oily/tan/white?)
I dont see any linkage clamp on the throttle butterfly. Just an arm with a neoprene bushing that rubs against the coil plate. Any other ideas? Or is there an adjustment and I just can't see it.
OK, now we're getting somewhere. This must be your 2nd carb right?
That's not a '72 25hp carb you've got there. More like around '75. The '75 was adjusted not by loosening the clamp, but that brass link rod you see was in two parts with a clamp holding the two parts together.
So you've got no adjustment there at all. You'll have to figure out how to get some in order to do the link & sync. I'll bet it's way off though.
Also, there's supposed to be a link running between the choke butterfly arm and the throttle butterfly arm. This opens the throttle a little when the choke is applied. You probably are getting a little hard-starting from that being missing.
This is the 2nd carb. I still have the first one though, and it does have the adjustable link. It will be going back on tomorrow, as there was nothign wrong with it in the first place. I never had an adjustable arm that applied fuel while it was choked. I had an electric choke solenoid which I just took off because I didn't have it hooked up and wasn't using it.
So let me get this straight - If I put the other carb back on tomorrow, the carb should just start opening between the two lines on coil plate assembly, correct? And I can adjust this by the adjustable arm on the butterfly plate arm, as shown in the diagram you posted, correct?
Correct. You want to set so it happens when it precisely mid-way between the two marks. This is a critical adjustment for good running at part throttle and is very important for fuel economy.
The link between the choke & throttle plate was only on the later carbs, not the '72. That's not the first one I've seen missing though - I think they fell off rather easily.
Sorry, I've been gone. Seems like the experts have you going in the right direction. The reason I mentioned the reed valves is because you said that fuel was being pushed back out of the carb. A flashlight in behind the carb will show anything that is sitting in there. Could be junk from your insulation or anything else. Glad there wan't anything there. You said it is not leaking anymore so I guess you had a bad gasket. Stay with 87 octane anything else is a waste of money. If you go to a higher octane rating you run the risk of predetonation.
Update: Seems to be fixed. Thanks for all who replied and pointed me in the right directions. I actually had to swap the butterfly and throttle arm out of my old carb into the new one. What a pain that was. But, I think I got it where it needs to be. I didn't notice any skipping or loading up. Of course, I took a screwdriver to the lake with me in case I had to adjust the arm again, which I did, but all is well. Thanks!
1972 Evinrude 25hp Fuel Leak
Linear Mode
