Forever to top speed, 86 50hp evinrude

[Smz rude 86]

What's happening:
Starts and idle excellent. Forward and reverse shifting with no issues. I slowly open it up to WOT. It stays at 8 mph for about 2 minutes then climbs up to 22 mph at 1 mph increments every 20 seconds. Only problem. Is before this happened the boat was running great and hitting 30 mph.

What I have done:
new cranking battery.
Changed tank pickup.
New fuel pump.
New fuel filter and lines.
Cleaned carbs fully.
new prop.
Multimeter tested coils (both good)
Changed spark plugs, lower head has perfect settings. Upper head came out wet.
Check plugs removed from head and both have spark, but upper head looks weak.
Battery is charging fully at 13.1 lots at WOT.

My thoughts:
Power pack issue as there is proper spark with timing and coils test 0.3 ohms and have spark?

Please tell me your thoughts on what's likely going on. Needs some help from a forum I have lurked for years. Motor was working perfect before my week off.... Balls...

Thanks for your help.

 

[TrueNorthist]

You need to check spark with an air gap tester, seems 7/16ths is the go to gap in these parts and I have zero reason to doubt such sage wisdom. Betcha find one plug wire is stingey with the zap. Full testing procedure is available in multiple threads in this sub forum. Search is your friend.

 

[flyingscott]

Do a compression test. Is the new prop same as the old prop?

 

[Smz rude 86]

Changed both spark plug wires for 28 bucks (forgot to add that to the what I've done list...)
checked compression and reading 128 upper and 135 lower... I'll have to wait to get a spark gap tester.

 

[Smz rude 86]

Prop is different but I put the old one on to confirm and still running at the 22 mph.

 

[TrueNorthist]

I'm only gonna add for posterity, that one exercise extreme caution testing removed, grounded plugs. Several times I've seen guys set fire to themselves and worse, the engine that way.

 

[Smz rude 86]

Lol I agree. I work on motorcycle engines a bit and have tested too close and sent out a fire ball. I had and extra new plug I used to test on the removed wires. No joke man. Scared the crap out of me when it happened once...

 

[TrueNorthist]

Buddy put in ~200 hours and hawked his old lady's jewelry to restore an early 60s Landrover. While troubleshooting a flooding issue he pulled out the plugs to purge gas and forgot to disconnect the coil. Whoosh. His wife left him, took the dog too and the worst thing, the whole Landover burnt to a cinder. He's pan handling for food these days.

Seen a fella use WD40 to dry a wet dizzy on a '63 Ford Econoline and didn't wait for it to evaporate. Same result but worse, his wife didn't divorce him.

 

[iggyw1]

Could there be floatation material under the floor that is saturated with water?

 

[Smz rude 86]

Unfortunately no. It was replaced last year and no holes in the boat. Literally had it doing 30 mph in the morning and only capably of 22 in the afternoon. I should also note, that even those there is spark on both, it's shacking and you can hear a miss fire even after checking timing.

 

[flyingscott]

Is the timer base moving smoothly?

 

[Smz rude 86]

Seems to be no resistance or binding but I will have to wait until I get home to tear into it more. And now a new update.
wont start anymore. Cracks and randomly fires once at the end of the ignition every 3-4 tries....

 

[racerone]

Checked flywheel key ?

 

[Smz rude 86]

I haven't but I will add that toy checklist.
im going to have to wait until tomorrow to see if I'm even getting continuous spark on both plugs now.
Flywheel key damage would cause it to be out of time and miss fire?

 

[oldboat1]

Change out plug wires and connectors.

 

[Smz rude 86]

Already did that.

 

[racerone]

A sheared flywheel key will throw it out of time.----Note---- you can not find a sheared key with a timing light.

 

[TrueNorthist]

The key usually fails advanced and will cause backfire and noticeably poor running at all rpm, if it starts at all, unless only slightly sheared (common). Sometimes one can discern the state of the flywheel key merely by removing the nut and washer, but its a cheat really.

A tensioned puller and a firm, straight on tap on the top of the puller screw usually pops the flywheel, or a light series of gentle taps around the flywheel. Light oil helps too. I usually use an air-impact hammer with blunt drift bit on the top of the puller screw to ensure success. That can easily damage the puller etc so again, careful secure alignment is a must. A quick squeeze and pop! Use the nut to protect the threads and never lever on the crankcase.

I've assisted things with a puller and lever combined, but used the lift hook or a wood block as fulcrum. I'd strongly advise against heating.

 

[Smz rude 86]

Awesome. Thanks guys. Traveling home today and we get things in order and report back once checked!
great advice on the disassembly too!

 

[Smz rude 86]

Ok update. Removed the flywheel and the key wasn't spun, but it definitely slid down and out of place which is extremely odd. My guess is the previous owner removed the flywheel and didn't seat it all the way, allowing for it to slide down?

I out the new key and flywheel back on and now have spark back but super weak.
What now master yoda?
She cranks but won't fire with that little spark..spark