1989 Evinrude 200 not reaching W.O.T. after 20" conversion

[jaymalyon]

Attachment 436056

On the water now. Checked timing as wide open as I could (still 3900) and the pointer is on 20 degrees on the starboard side of the scale. I know I'm looking for 18 degrees but the only mark I can see is on the port side of the scale on the flywheel. Is it possible my timing is that off? Seems like a hell of an adjustment.

Timing at 3900 rpm

[mrichartz]

If you happen to find an extra I'd be happy to buy it off you!
Still not 100% on if I've got the timing set right.

Ok found 1.. I guess they're getting even
scarcer Thought I had 2

[Nitro25]

TroubleShooting Bucket List

Best to do these checks when engine is hot and is failing.

1) Ck Compression all cylinders (Warm Engine, all Plugs Out)
2) Ck ignition at coil terminal (KV Meter or Spark gap tester)
3) Ck ignition at spark plug wire plug end. (Test all wires for resistance Ohm Meter)
4) Check fire on spark plug electrodes.
5) Check that center anode porcelain insulator cannot migrate down to ground electrode. (Ya I know, but it happened to me more than once)
6) Check Charge coil output (Plugs out)
7) Check trigger output while manipulating timer base back and forth. (Plugs out)
8) Run Engine on hose and perform cyl drop test.
9) Check Alt output test volts and amps. Voltmeter at battery, ammeter in series between v/r red wire and start solenoid. (If bad result remove pack and look for hole in potting where the smoke came out. Test pos and neg diodes in v/r.)

There’s your systematic basic checks, do them all and record results. Even the comp check, you may have damage since the last check due to lean running. Take nothing you think you know from previous checks for granted. Stay focused and get these out of the way.

More advanced checks.

1) Degree #1 cyl for accurate TDC indication using piston stop method.
2) Degree the rest of the cylinders for TDC and then for WOT timing. Use flexible machinist steel rule to transpose the distance from TDC to WOT figure.
3) Get someone the drive the boat and check WOT ignition timing, this is critical, mark factory recommended timing on flywheel grid with yellow or white paint to see easier. Set your worries about timing aside here, all your concerned about is “Where is my engine timing at WOT.”
4) If WOT timing is amiss set WOT timing with timing adjustment screw.
5) Move timing light to all other cylinders and check for appropriate timing. What you’re really looking for here is the pack double firing or scatter firing. You’ll see two grids superimposed over each other solid or intermittent (Ghost) If you have this situation.
6) Remove flywheel and very closely inspect inner trigger magnet ring for signs of migration or deterioration. Chips, “Hairy” accumulation of debris sticking to magnet hub.
7) Check charge coil magnets for migration. See if you can twist the hub by hand of very gently with chanel locks avoiding the magnet windows.
8) check key & keyway for damage or shearing.
9 Attach vacuum gauge to inlet side of VRO, and PSI gauge to outlet side via clear hose, after priming engine, you don’t want to hurt vacuum gauge. Test run and check readings, and look for air intrusion/ especially on the outlet side. (Bubbles/Foam) The Vacuum spec used to be 7 inches, I believe it might be 3” now, but Mercury specs might be bleeding into my brain, check your manual. Bubbles/Foam=Bad VRO.

Now for the weird. Run engine on hose and rev engine to around 2000/2500 and see if there’s more exhaust presence coming out of the exhaust relief ports above the anti-ventilation plate than the prop exhaust. If so, drop gearcase and look for dead Squirrel! (Don’t ask) Or something like a shop rag or so forth blocking exhaust.

As you see other ideas on this blog write them down, but do these first and check them off the list. This will either discover what’s going on, or at the very least create a base line of what’s not out of spec.

Lets us know you results.

Good luck;

D.

[jaymalyon]

Ok found 1.. I guess they're getting even
scarcer Thought I had 2

PM Sent

[Nitro25]

Where your finger is pointing is starboard. are you saying your reading is 20* "Right" (Port) of TDC?!!

[mrichartz]

Your only 2 degrees off on wot timing
Should be 18 btdc..
Did you check the tdc on #1
..marks on flywheel are correct ?
And nothing was ever done to motor any work ?
It's marked at 16 btdc which is usually if compression raised or work was done to it..

[mrichartz]

Where it's marked.. A at 18 is not what you want that's atdc...that 4* is the idle

[Nitro25]

Ok, when was the last time you had the air box cover off? Pull the cover and check all carb butterflies for full opening. If you didn't get the sync screws tight enough after rebuild, and some of the lower carbs came lose, and are not opening all the way, this would cause this event your experiencing EXACTLY!

[Nitro25]

Ok, when was the last time you had the air box cover off? Pull the cover and check all carb butterflies for full opening. If you didn't get the sync screws tight enough after rebuild, and some of the lower carbs came lose, and are not opening all the way, this would cause this event your experiencing EXACTLY!

Yep ... Think about it. If the tension is just right on a sync link screw, at times it might open the butterflies along with the other carbs, maybe when engine is cold. But at other times it will be too loose to open the offending carbs but say a 1/4, say when hot. They're spring loaded so when you bring the throttle back to idle they'll close and not give an indication that anything is wrong like a lean sneeze. I'l bet this is what's happening!

[Nitro25]

Yep ... Think about it. If the tension is just right on a sync link screw, at times it might open the butterflies along with the other carbs, maybe when engine is cold. But at other times it will be too loose to open the offending carbs but say a 1/4, say when hot. They're spring loaded so when you bring the throttle back to idle they'll close and not give an indication that anything is wrong like a lean sneeze. I'l bet this is what's happening!

The screw #47 is not tight enough on Coupler #37

[Nitro25]

The screw #47 is not tight enough on Coupler #37

https://www.crowleymarine.com/johnso...cfm?mdl=35RUJW

[jaymalyon]

Yep ... Think about it. If the tension is just right on a sync link screw, at times it might open the butterflies along with the other carbs, maybe when engine is cold. But at other times it will be too loose to open the offending carbs but say a 1/4, say when hot. They're spring loaded so when you bring the throttle back to idle they'll close and not give an indication that anything is wrong like a lean sneeze. I'l bet this is what's happening!

Interesting theory. I've checked to see if they are opening all the way with the engine off in the driveway. But never after it has warmed up out on the water. Worth a shot.

Thanks for the checklist, that's very helpful. I'm going to work my way through it and report back.

[jaymalyon]

BTW, I've never touched the linkage on the throttle plates. Just pulled the carbs off and left all that alone.

[Nitro25]

BTW, I've never touched the linkage on the throttle plates. Just pulled the carbs off and left all that alone.

Probably not it then ... crap!

It's got to be something so freakin simple, wish I could pop over to Ga. and help you with it.

One more thing for your scratch pad. Run without the air box cover on. Get a driver, and a spray bottle that will atomize fluid, and put a bit of gas in it. At WOT spray a bit into each carb throat and see if you get a response in power. Make note which carbs are running lean.

If memory serves, some after market carb kits had inlet seats that were too small, did you use factory kits?

D.

[jaymalyon]

Probably not it then ... crap!

It's got to be something so freakin simple, wish I could pop over to Ga. and help you with it.

One more thing for your scratch pad. Run without the air box cover on. Get a driver, and a spray bottle that will atomize fluid, and put a bit of gas in it. At WOT spray a bit into each carb throat and see if you get a response in power. Make note which carbs are running lean.

If memory serves, some after market carb kits had inlet seats that were too small, did you use factory kits?

D.

The way things are going I might be inclined to drag it down to you!

Would aerosol starter fluid do same thing? Spray bottles of gas sound pretty scary.

Yes on the factory carb kits.