Help. Elusive Evinrude problem...no one has been able to solve

[Mrk Hollowell]

I have a 1980 16 1/2' aluminum boat with a 1984 2 cyl. 60hp Evinrude motor.

Was running great, fast as can be--45+mph.

Then, all of a sudden, it dropped to only about 20% of full power--about 15 mph.
It starts fine, revs loud and fast when the start fast idle lever is in the up position. It idles good, it runs smooth at full throttle but with only 20% of the speed. Arghhh!!!

Talked to three boat mechanics.

One said to replace the fuel pump--I did and nothing changed. Same symptoms

The two ignition coils produce strong blue sparks for each plug when cranking and grounding against the motor.

The spark plugs look fine - completely normal...not soaked, not dark, not fould, just normal.

Compression in each cylinder is identical: 148 pounds

Prop tested OK for torque at a prop shop

It runs fine in reverse, though I never go fast. However, it did super rev in reverse while trouble shooting it on the lake a week ago--that's when I thought that the prop was spun--tested OK.

Fuel is new, with the proper 50:1 mix, and has a clean screen filter in the plastic gas tank and a new in-line filter--replaced yesterday when I rebuilt both carbs.

I pulled and rebuilt both carbs yesterday. THe bowls were clean and all jests wer clean.

I started it up after rebuilding the carbs and it ran great with ear muffs--reved incredibly fast. Granted, there was no load on the prop...but it, nonetheless, screamed with no missing at all.

The throttle linkage opens both carbs up all of the way.

The manual and electric choke work as they should.

Took it to the lake this morning and it runs exactly the same as described above; starts fine, revs great in high idle position with fast idle lever in up position, runs pretty smooth at low throttle, but when I move the throttle all of the way forward (Slow or fast), it only goes to 20% throttle and speed. It creates a wake, but it's just not at the power level it was.

When I tried to drop the lower end last weekend, the gear oil was perfecly clear and there were no metal filings or shavings in the gear oil. As I am a novice mechanic, I could not get the lower end to fully disengage so I could not drop the lower end all of the way.

I'm told it could be timing, wiring short, drive shaft spoine worn at lower end or powerhead, air leak in fuel system...

I give up...just about! I just want a nice, fuin boat running again at full speed.

I need a good boat mechanic to diagnose and repair the problem.

Please call or email me.
Thanks for reading this far.
Mark
602-576-3058
mark@markmediagroup.com

 

[tashasdaddy]

Re: Help. Elusive Evinrude problem...no one has been able to solve

i'm not familar with your particular engine, and don't know if it has this feature. when the temperature sensor detects the engine is running hot, it will kick the engine into SLOW mode, to help from damaging the engine. it sounds if your engine is so equipped, that it is in slow mode and has not reset. or the sensor is bad. hopefully someone will be along soon that knows for sure. good luck.

 

[dreamchaser]

Re: Help. Elusive Evinrude problem...no one has been able to solve

Have u tried to pump the primer bulb while under power? sounds like fuel to me .... m2c

 

[JB]

Re: Help. Elusive Evinrude problem...no one has been able to solve

Howdy, Mark.

Welcome to iboats.

Revving with no load is of zero use when power is down. It will do that on one cylinder. You did not mention engine rpm when it is wide open and going nowhere. That is important.

First, confirm that both cylinders are making power. Disabling a spark plug at idle should cause a drop in rpm. If there is no drop that cylinder is not making power. If it dies the other cylinder is not making power.

NEVER rev a 2 stroke to WOT when not under load. A thermal runaway could destroy it.

If you have a dead cylinder some possible causes are:

* Carb not feeding fuel. Squirt some fuel premix into that carb. If rpms go up, clean the carb again.
* Broken or bent reed.
* Leaky bypass cover gasket or intake manifold gasket.

If you do not have a dead cylinder, some possible causes are:

* Linkage not advancing timing or not opening throttle plates completely.
* Sheared flywheel key and slipped flywheel.
* Carb synchronization waaay out.

Let us know what you find, and good luck.

 

[Joe Reeves]

Re: Help. Elusive Evinrude problem...no one has been able to solve

As per one of JB's mentions (Linkage not advancing timing).

Look at the top portion of the vertical throttle/spark advance linkage on the starboard (right) side of the engine. There is a "L" shaped linkage there which is attached/secured by a "Ball & Socket" on each end.

Those Ball/Socket assemblies have been known to fail which allows the linkage to snap out of the retaining ball. This results in no control over the spark advance (timer base) and in effect..... the engine is running with the spark retarded at all speeds.

 

[Mrk Hollowell]

Re: Help. Elusive Evinrude problem...no one has been able to solve

JB, first, thanks for the welcome to the site. Second, you hit it. The top cylinder is dead. Pulled the plug, nothing, pulled the second and it dies. Reversed it--left dead cylinder plug connected, pulled the bottom cylinder...again, it dies. Put on ear muffs (on the boat, not me), started the boat, gave a short shot of carb cleaner to the carb and the motor sped up. Stuck it in gear at moderate rpm, and again, it sped up.

I'm certain that the carb rebuild was good and that all jets and ports are clean and functional; but, I'll do as you suggest, and clean it again.
More Questions:
Don't know where the reed valve is; is it down in the manifold? The manifold appears to be one manifold for both carbs--do I have to remove it to replace reed valve? How do I know if the reed valve is defective?

Where is the bypass gasket that you siggested might be leaky? How do I know if it's leaky? Any way to test?

You've been a big help. I should have started with that simple pull the plug test. Oh well! Guess I shouldn't quit my day job for a boat mechanic job anytime soon.

Mark

 

[kynolan2183]

Re: Help. Elusive Evinrude problem...no one has been able to solve

If (from what I read) you pulled the top plug and it did not stall out and die but you reversed it and it did stall and die, do you have spark on the #1 cylinder?

Check for leaking spark from bad wires. Do this at dusk.

 

[Mrk Hollowell]

Re: Help. Elusive Evinrude problem...no one has been able to solve

I pulled the top spark plug and nothing happens. Leave it pulled and pull the bottom plug and the motor dies.
Put both wires back on and then pull the bottom plug only and the motor dies.
Spark plug is bright and blue spark when grounded to the top of the cylinder.
Compression in each sylinder is 148 pounds.
Will check for leaky plug wire at dark, as you suggest.
However, when I shot a short burst of carb clearer down the carb throat, the rpm increased--both at idle and with the propr in gear and running at a higher rpm. I'm simply not getting fuel to that clyinder.

Don't know what a reed valve is or where its located, if that is the problem.
Mark
Mark

 

[BoatBuoy]

Re: Help. Elusive Evinrude problem...no one has been able to solve

From what you wrote, one cylinder is not getting spark. I'd fix that before trying to fix something else that may not be broke.

 

[kynolan2183]

Re: Help. Elusive Evinrude problem...no one has been able to solve

You will see the leaking spark and be careful with carb cleaner it does not have the oil your motor needs.

Get a squirt bottle with per mixed fuel and use that. I don't think that you have a bad reed or you would hear it hissing and the steel reeds in an Evinrude are life long reeds in most cases.

One thing to check is that the vent hole to the carb bowl is open. This allows air to go out as fuel comes in

Kyle

 

[Mrk Hollowell]

Re: Help. Elusive Evinrude problem...no one has been able to solve

Vent hole on the carb? I did not see one when rebuilding the two carbs.

 

[clemsonfor]

Re: Help. Elusive Evinrude problem...no one has been able to solve

The plug pulling test just confirms that there is a dead cyl. not that there is no spark, you need to ground that plug or wire while running/cranking to confirm a spark. But by spraying carb cleaner in the carb (a no no like said as it has no lube and washes the oil off bearing and cyl walls) speeds up the motor meaning that that cyl is now firing it means you are not getting fuel to that cyl to fire. Check the carb and all fuel lines running to it for leaks stuck floats or needle valves.

-Nate

 

[Mrk Hollowell]

Re: Help. Elusive Evinrude problem...no one has been able to solve

I want to thank all of you for succeessfully leading me to the most likely cause--no fuel to the cylinder. I pulled the carb and a nearby boat mechanic is going to take a look at it. I was not correct when I said I rebuilt it. I pulled it apart and sprayed it with carb cleaner and blew it out, pulled all jets, float, needle valve, and seat, but I did not replace any of them, nor the gaskets. After he gets done actually rebuilding it, I'll try it again. If it's still running on one cylinder, I'll look agian for air leaks in the fuel system and get back to ya'll. Again, thanks for helping me out!