67 evinrude 80hp loss of power on #2&4 cylinders

[jtwags]

I am having a problem with a 1967 evinrude 80hp Starflite electric shift outboard. I pulled the boat out for the summer (sat for seven months) Added 3/4 tank fresh 50:1 gas. Found I had no spark, found coil had cracked and was bad. I have the battery points/coil ignition. I couldn't find a replacement coil so I put one of my VW coils on and ran a 12 v wire to the coil from ignition. Engine now runs, but I couldn't get enough power to plane out while on the water, only get about half throttle and motor felt weak. Since then I have rebuilt carbs (squeaky clean), new fuel filters, pump bulb. etc... I reconditioned distributor cap, refit all wires (all ohm out great), cleaned and set points with continuity light (points are one year old, less than 10 hours on them). Now the motor idles great, but I noticed as I pulled the plug wires off the port cylinders (2 and 4) it only caused the motor to stumble a little (the engine continues to run with a little difference but not as much as 1 and 3, indicating weak combustion). When I pull the wires from cylinder 1 or 3 the engine will die during idle (indicating strong combustion from 1 & 3). I swapped the wires and spark plugs around and still cylinder 2 and 4 seemed weak (wires and plugs not the problem). This seems to indicate that 2 and 4 are not producing the power they should be and I am not sure why. Both cylinders are getting good fuel supply. When I remove the spark plug wires the spark jumps across to the plug with strong blue spark and I hear the cylinder fire. I refiled the points and put in my spare condenser and set the points with continuity light. Still find that cylinder 2 and 4 are not producing their fair share of power. I am at my wits end!!! Please Help :%
Thanks,
Jason

 

[KYHunter2]

Re: 67 evinrude 80hp loss of power on #2&4 cylinders

The motor should not die when individual wires are pulled.

Just be a noticeable change in rpm's , as each is pulled individually.

Do a compression test , but first get the correct coil.

At least , I would , Vw may make outboards , I don't know.

I do know yours , aint one , correct.

As started , comp. test , correct spark test.

I have had a similar problem , in the past.

I'd pull wires with engine running , when # 4 was pulled , motor died .

Odd thing , problem was weak spark on #3, (opposite bank).

I guess # 4 , was trying to take up slack for #3, and when #4 pulled .

It was in effect, trying to run on 2 cylinders., and a misfiring one.

Due to bad plug wire connection/ wire.

Its , what sounds like a spark issue.

Check all grounds , need to be shined up and tight, seal with grease, or liquid elect. tape.

I don't think its a good idea, to use parts from other motors , nothing like the one You have.

Coil may work fine, I just don't need to create possible problems .

Do the ignition trouble shooting , for your motor, its in your manual.

KYHunter

 

[jtwags]

Re: 67 evinrude 80hp loss of power on #2&4 cylinders

Thanks for the response.
I did all I could on testing spark short of using a peak voltage output meter. I reconditioned the cap and wires. I even swapped wires and plugs to other cylinders and #2&4 still seemed to be less powerful with the other plugs and wires. You are right the engine is dying when I pull the wire from #1or3 because they are burning properly and 2&4 aren't, thus creating the dilemma. I am having trouble finding an exact replacement coil for this motor. I have read using an automotive coil should work fine. Maybe I should buy an MSD ant-vibration blaster coil as that is epoxy filled. I am going to try switching the points just to make sure they are not the problem. Could this be a mechanical problem, intake or exaust valve issue (reed)?

 

[KYHunter2]

Re: 67 evinrude 80hp loss of power on #2&4 cylinders

Running rough , can be caused by an open or damaged reed valve. But, more common things can be misadjusted floats, improper link and sync. dirty carbs, spark issue etc.

What do the plugs look like ,after you run the motor for awhile?

When you rebuilt carbs. Did you install new kits ,or just clean and reuse old parts?

You really need a manual .

Then you can test, and eliminate possible problems, in some type of sequence.

Loss of power in one bank, can be caused by several different things.

Verify spark , compression , carbs properly rebuilt/ adjusted, link and sync. done correctly, all connections clean and tight.

Correct plugs , fuel ratio correct , etc. etc.

You get the idea.

Its much easier for everyone , trying to help .

If you follow a trouble shooting procedure .

And either find the problem ,or find symptoms , that will help in trying to diagnose, your problem.

Until you get a manual , just start with a comp test, spark test , verify fuel delivery is correct .

And that the carbs are in sync, as in link and sync.

Thats really about it in a nutshell.

Fuel , spark ,compression.

Have you ever done a thorough decarb?

If not give it a try also.

Im still leaning towards a spark issue.

But, then again there are alot of guys here , that are more familiar with the older motors then I am.

Maybe, they'll drop in with some advice.

Good - Luck,

KYHunter

 

[jtwags]

Re: 67 evinrude 80hp loss of power on #2&4 cylinders

Here is my checklist so far: (used manual’s testing procedures)
1) compression is 90-91 psi on all cylinders
2) eliminated fuel starvation as a problem, tested on water with squirt can of premix (no changes) carbs rebuilt last year with new kits. Took apart and cleaned again.
3) reconditioned cap, plug wires.
4) Swapped plug wires around and spark plugs around (didn’t change anything) J4C champion plugs. Plugs from 2 & 4 seem to be little dirtier and appear not to be burning as well!!! Hint!!!
5) Decarboned engine with sea foam and deep creep. (no change)
6) Removed head from 2 & 4, looked great, light carbon, clean looking ports.
7) Synchronized carb and distributor to exact tolerances (made a little difference but not much)
8) Swapped points and condenser (no difference)
9) Removed stuck open thermostat (more water comes out now, but made no difference)

All I have left is the fact I have an automotive coil on and not a stock OMC externally resisted epoxy filled coil (which cost $100.00). Could this cause the port bank to fire improperly every time consistently? Is there any way to determine the condition of the reeds without pulling the motor apart? Any Help is always appreciated thanks for the responses KYhunter d

 

[KYHunter2]

Re: 67 evinrude 80hp loss of power on #2&4 cylinders

As I hinted to . Im far from an expert on the older motr's . (pre 70's ). But , you should be able to pull intake , and have access to reed assembly.

Look for deformed / bent reeds , open reeds , and thoroughly clean , while your in there.

That is if you have your heart set, on the reeds being your problem.

I'd build a spark tester , where you can check all cylinders at the same time.

There are different ways to do this.

What I did was, drill proper size holes for the spark plugs to thread into , in 1/4" plywood.

Then I epoxied 6 old plugs in to the holes.

I used steel wire , and tacked one end of a 8" piece of wire to the electrodes. ( you can just stick it on the electrode and smash contact down on it and epoxie).

That is if you have no way to tack them.

Then in the center of board I installed a bolt. (grnd)

I cut the wires , so they were all 7/16 " from the grnd. bolt.

Then on opposite side of board , I attached a couple fgeet of wire with a ring on one end for the bolt to attach to, and a ground clamp on the other.

The board is about 10" wide , and 2' , long.

Just hook ground clamp to good ground.

Plug plug boots onto plugs and have at it.

Mine stands up nicely, between the heads on the 4 and 6 cylinder motors.

Then you can verify that there all firing and notice any serious discrepancies (spelling) , between cylinders.

It seems you been over most everything else.

But, as I indicated previously.

When a normally good running motor , isn't all the sudden.

I'd look at anything thats been done recently , and procede from there.

ie: the odd coil.

As far as if it's your problem , Im not sure.

But, I'd be sure to get the proper one regardless.

Thats just what I'd do and allways have if possible.

Be it car, motor cycle, ATV.

I just figure ,if thats what the factory saw fit to use, why change it , its been working.

I do use some aftermarket parts , alot.

So far , Ive never had any problems.

Good-Luck,

KYHunter

 

[StratosRob]

Re: 67 evinrude 80hp loss of power on #2&4 cylinders

Have you done a complete fuel system check? If not I recommend it. Anything to do with the fuel system can create electrical type symptoms.

 

[jtwags]

Re: 67 evinrude 80hp loss of power on #2&4 cylinders

I did everything on the fuel system, new filters, primer bulb, cleaned carb, cleaned and checked fuel pump and gasket for leaking. Everything checks out. I think I found a bas Spark plug though, Brand New - Go Figure, but it hasn't completely eliminated the problem. I am going to have to run it up to an old timer out here to trouble shoot with some of his old time testing equiptment and he has the parts on the shelf to test. I will update again soon.

 

[Solittle]

Re: 67 evinrude 80hp loss of power on #2&4 cylinders

I don't know the 67's but if you have two coils swap em & if the problem moves - - - -

 

[jtwags]

Re: 67 evinrude 80hp loss of power on #2&4 cylinders

only one coil