850 Thunderbolt

[VAPirate]

Hello..

Can anyone help me understand if their is a serial number range to determine if my 1973, 850 Mercury Thunderbolt has either of these ignition systems.

Distributor CD Ignition, Or

Distributorless Ignition

 

[bryanwess2000]

Re: 850 Thunderbolt

I believe before 1976 and model number <4366802 is going to be distributor
ignition, I have a 1977 merc 850 and it has coil packs. check out maxrules to id your motor.

 

[Chris1956]

Re: 850 Thunderbolt

A '73 Merc 850 has a distributor-based ignition. Remove the wrap cowl and you will see it on the right front side. It should have a red band on the cowling. The single coil is the ugly red one on the left side, in the lower cowl.

Serial number should be on transom bracket.

 

[VAPirate]

Re: 850 Thunderbolt

Gotcha. Thanks. I just acquired the motor. I had the shop manual out with her this morning. The only apparent issue is the harness.

I am trying to justify $140.00 for the internal wiring harness now.

I never would have guessed that much. She starts and runs good. But I must replace that harness. The insulation has rotted away pretty bad.

 

[Chris1956]

Re: 850 Thunderbolt

Try Surplusunlimited.com. The harnesses are a bit cheaper

 

[VAPirate]

Re: 850 Thunderbolt

Oh I see!! Still with all the Merc's it fits, ya' might think this part would be a dime a dozen.