How to set WOT timing without test wheel?

[SteveVT]

I've read two alternate "non test-wheel" methods for setting WOT timing on the Johnson/Evinrude forum incl. "The Joe Reeves" method.

Is there something similar for Mercury/Mariner engines of my type?

(Mine is a 1989 Mariner 25hp EL two stroke. I have the Mariner OEM manual for that year, and know and can perform all of the other timing link and sync and idle adjustments, but performing the initial WOT timing adjustment safely, single-handed is the problem. The trigger coil has been replaced on this engine, and some of the linkages, so yes, I do need to time it, unfortunately.)

Thanks in advance!

 

[SteveVT]

Does anyone here time WOT without a timing wheel? Or without hanging off the tail of a speeding boat with a strobe?

 

[Texasmark]

Starter speed timing is in the service manual for both idle rough in and WOT. RPMs are specked at 200...good starter, plugs out, throttle at the idle stop will be around 0* for the initial tweak. On 90-115 engines WOT setting is like 20-22 BTDC depending on whether you set it with a test wheel or spinning the starter. Don't know the numbers for your engine but others on here do and will probably read my reply and fill in the missing blanks.

On the mentioned engines, idle timing how you set the idle speed. Boat in the water, in F gear, in motion, throttle at idle, 650-700 rpm using the idle linkage knurled stop screw...turn with your fingers and lock it down.....fast enough to keep the engine from stalling when shifting out of N and slow enough to shift without grinding....would imagine your engine is set similarly.

 

[Faztbullet]

Pull the plugs and ground em out, attach timing light to #1 cylinder, use starter button or jumper wire to activate starter solenoid as will need to be in gear and at WOT. Set timing to 21° and your good.

 

[SteveVT]

Thanks Texasmark. I have the original Mariner service manual for my year and engine. WOT timing is supposed to be 25 BTDC. My Idle timing w/new starter, plugs out, and charged battery is 0 degrees. Manual says 0 to 2 deg ATDC. So that's okay. I will check WOT timing with the starter method. Manual says my idle speed should be 700-800. I can't reliably hold that. I need about 1000 rpm. I have tried to adjust idle mixture, to help lower it, but it is too rich with anything other than the idle screw all the way in. I'm guessing the reason is a worn idle needle or seat. It does okay with that closed setting. It doesn't cough at idle. If anything it still feels a slightly rich, and that's probably why I can't run at 800. It tends to 4 cycle at lower speeds, purrs at 1000. That's my guess, but I'm open to others on that judgement. Wear isn't surprising. This engine is 31 years old, and I did 1700 miles with it in the 90's down the Intracoastal and across Florida pushing a 31' 10,000 lb houseboat that I built. Thank you again for advising.

 

[SteveVT]

Faztbullet, sorry I answered TexasMark before I saw your post. Is the 21 degrees you mention because you subtract 4 degrees from the manual WOT timing of 25 degrees, per "Joe Reeves Method"?