1998 merc 5.7 how do i set timing need help

[jws123]

I have a 1998 wellcraft 240 SE with a 5.7 merc THUNDERBOLT V ignition 2barrl just took it out of the slip been having power issues so want to check timing i dont have a book new enough for my boat guess i gotta get a new one what should the timing be set at?

 

[jws123]

also i dont have timing numbers on my cover just 1 mark on damper and 1 slot on timing cover so how do i set it?

 

[porscheguy]

You need an advance timing light. You need to run the engine until it’s fully warm. Then you must shut it off and use a jumper wire to place it in base timing mode. There’s a purple wire near the carb that doesn’t appear to be connected to anything. Connect one end of your jumper to that wire, and the other end to a good ground. Connect your power leads on the timing light to 12v and ground. Connect the remaining wire to the number one spark plug lead. This is on the front of the engine on the port (left) side of the boat. Make sure all wires are clear of moving pulleys and turn the engine back on. Set the advance on the light to whatever it says on the flame arrestor. Should be 8 or 10. Aim the light at the engine and if the timing is right, the marks will line up.

 

[Scott Danforth]

if you dont have an advancing timing light, spend $5 on timing tape

as for low power, most likely its fuel system related and not the ignition

 

[alldodge]

Assuming carb 5.7
Timing 10 BTDC
Idle 650 rpm

Ground the Purple/White wire coming from the ignition module (or harness) that has a female banana jack end
Start the motor and warm it up to operating temp or have it already warm
Adjust idle to spec
Adjust timng

There are different options for adjusting timing, but easiest is with an advance timing light. Adjust light to 10 BTDC then adjust distributor to the mark on damper. Probably get a loaner at the local auto store

Other methods are but using timing tape and tape it to the damper (can be found at most auto stores). Other method is calculate the circumference of the damper and make your own marks

 

[jws123]

OK thanks guys i think i got it set will see how it goes i borrowed a advanced timing light just installed new prop on boat had to take it out spun the hub so giving it a once over before i put it back in,