67 evinrude selectric - loss of power, leaking problems

grease · #1 July 17th, 2006, 10:47 PM

I have a 1967 Evinrude Big Twin 40hp selectric. I took it out on the water for the first time this summer and it ran good for about 15-20 minutes.

1. Then i started losing power going forward. I had throttle wide open and probably only had 25% power. If I shifted into neutral, it would rev real high, like it should. Put back into forward, it chugged along.

2. Upon pulling it out of the water, noticed a gray discharge coming from a couple different places. Assuming that oil and water and emulsified.

What is the damage here? Is this something I can fix myself?

Tim

tashasdaddy · #2 July 17th, 2006, 11:18 PM

check plugs, and compression and spark. couple of different places don't tell us anything, like where?

Paul Moir · #3 July 18th, 2006, 12:53 AM

Good spark will jump 3/8". Extra rich or missing due to bad spark, etc, causes a discharge like that via the exhaust and all the little weep holes that open into the exhaust area.

The spark plugs will tell a story, if one's wet then it's likely ignition or the fuel pump problem. If they're both black and damp, most likely there's a carburation problem.

grease · #4 July 18th, 2006, 11:34 AM

I'll take some photos and post tonight that will show the gray discharge. I know I am being vague, but not sure what each little hole is...other than a drainage hole, as mentioned in other forums.

I may have added too much oil to the fuel, if that would cause any of the symptoms above.

itstippy · #5 July 18th, 2006, 11:06 PM

Paul Moir says check the spark so you should do exactly that.

Go to a hardware store that has an automotive department and get a spark gap tester. They're about 4" long and about $7. I got mine at Harbor Freight. Not the kind that lights up - those don't tell you how strong a spark you have. You want the kind that clips to the motor somwhere where there's bare metal (to ground it) and the spark plug wires can reach it and it has an adjustable gap for the spark to jump across. Pull both spark plugs and hook the plug wires one a a time to the gap tester. The tester has a nipple on one end just like a spark plug. The gap tester is adjustable and you should set it at at 3/8". When you turn over the motor the spark should pop across the gap in the tester with a "Snap" and be blue. Post the results.
In my limited experience the 40HP Big Twins have trouble with a 3/8" gap but if they jump a 1/4" with blue spark and "snap" they run well. They seem to have wimpy spark for some reason. Maybe it's just the ones I've messed with though.

grease · #6 July 19th, 2006, 09:57 PM

I have some photos of the grey leakage..it is mostly from lower unit. Also a photo of the spark plugs I pulled..not looking good. I plan to empty the fuel tank and get a fresh careful mixture of gas/oil.

Engine model is: 40772E
spark plugs: Champion J4C 9 (Can anyone verify this is the correct one..they are from previous owner)

Paul Moir · #7 July 19th, 2006, 11:08 PM

J4C is correct. Those are two very rich looking plugs you have there. So you're apparently running pretty rich, and one is probably fouled.

When you pump the primer bulb, does any fuel come out of the main jet in the carburetor?

Black oil gunk is typical in those places if you're running rich or fouled. I wouldn't be concerned about the oil mix unless you went pretty far beyond 24:1. 50:1 with a little extra should be no problem.

itstippy: I agree, a BT has trouble making a spark 3/8" long normally. But if the ignition system is perfect is should be able to do it, not every revolution but occasionally. It should jump 1/4" pretty well though. I think you're right though, I should probably tone it down for the BTs.

grease · #8 July 20th, 2006, 09:26 AM

Is the grey leaking ok though? Do I need to flush the fuel system before replacing the plugs? If so, how.

DJ · #9 July 20th, 2006, 09:31 AM

You are looking at unburned fuel/oil mix. It becomes grey because the exhaust housing is water cooled.

The plug on the left looks wet-not firing properly.

Get the spark tester, as mentioned.

If one plug stops firing after warm up, it is most likely a coil. Easy to check by swapping them around.

Did you ever service the lower unit lube and the water pump? If not, you're due.

grease · #10 July 20th, 2006, 01:12 PM

I just changed the lower unit lube and also greased the ports as mentioned in the manual. Water pump..I am not sure what the maint history is on it.

grease · #11 July 24th, 2006, 10:11 AM

I put in new spark plugs and put in a decarbonizer solution into a fresh tank of fuel and took it out on the lake with no change.

Think I am running on one cylinder. It did ok on slow speeds, but if I went faster, it would clunk out after about 30 seconds. Does that mean the one piston is flooding out b/c it is not burning off?

Where can I buy coils for this old boat? I see some listed on this web site but goes by part #, which I do not know.

Paul Moir · #12 July 24th, 2006, 10:59 AM

Coils are available both aftermarket and OEM. The aftermarket coils, which I personally like more than OEM, are Sierra PN 18-5181. Iboats, etc, sell them. The OEM ones are PN 584477.

But I've got doubts that's your problem. If you suspect it is, first conduct a spark test. A healthy system will produce sparks 1/4-3/8" long on both cylinders.

To me it looks like the carburetor is either flooding or the main jet is leaking. Possibly even the fuel pump is leaking fuel into the crankcase. The spark test will tell for sure though.

Don't rev these engines in neutral above 2000 RPM or so. When you do, they run lean of both fuel and oil, and you are inviting run-away. Not to mention the needles in the bearings tend to skate and flatten. It's just a bad idea on any 2-stroke, and an outboard especially.

grease · #13 July 24th, 2006, 11:35 AM

Thanks. Guess I will drop it off at a boat repair shop as I am not sure what to do on your suggestions. By the time I figure it out, summer will be over here in this northern country.

Quote:

Originally Posted by Paul

Coils are available both aftermarket and OEM. The aftermarket coils, which I personally like more than OEM, are Sierra PN 18-5181. Iboats, etc, sell them. The OEM ones are PN 584477.

But I've got doubts that's your problem. If you suspect it is, first conduct a spark test. A healthy system will produce sparks 1/4-3/8" long on both cylinders.

To me it looks like the carburetor is either flooding or the main jet is leaking. Possibly even the fuel pump is leaking fuel into the crankcase. The spark test will tell for sure though.

Don't rev these engines in neutral above 2000 RPM or so. When you do, they run lean of both fuel and oil, and you are inviting run-away. Not to mention the needles in the bearings tend to skate and flatten. It's just a bad idea on any 2-stroke, and an outboard especially.

grease · #14 August 2nd, 2006, 10:51 PM

UPDATE & HELP NEEDED: Boat has been at repair shop for last 1.5 weeks. They said the high speed needle is broken and they cannot remove it to replace it. They said i need a new $400 carb which they do not make anymore. Told me they cannot help me and to maybe find a used one on Ebay.

Does this really make sense? There must be a rebuilt kit for this? After reading much of the manual, the nice thing about this engine, the manual actually tells you how to test and repair each part, instead of today's method of disposing and buying new.

I am a novice to boating repair, but have a feeling they just do not want to repair this old boat and that this can be repaired.

grease · #15 August 3rd, 2006, 03:21 PM

I will end this post and start a new one.