650 Merc no spark

[jdahna]

I have a 1970? 650 Mercury outboard 4 cylinder with Thunderbolt ignition system with no spark. No serial number plate, was removed prior to my purchase of the boat. Dealer that I took it to says that the trigger and switch box is bad and the ignition system was only installed for 3 years by Merc and parts are impossible to find and bettter off getting a different motor for $1200.

Anyone have a trigger and switch box for this 650?

Is there a way to retrofit a different ignition system onto the motor? It has 110-112 compression on all 4 cylinders.

 

[usskydvr]

Re: 650 Merc no spark

What is the serial # on the engine. Need to verify the year.
If it is a 1970 an aftermarket swich box 114-2986 will run about $300
and the trigger will have to be sent in to a company like CDI Electronics
to be rebuilt. Also about $ 300.

 

[jdahna]

Re: 650 Merc no spark

I am not sure on the serial number. The plate on the transom was removed prior to my owning the boat. I didn't know this fact until I was cleaning the transom area on the motor and could see where the rivits were.

I have read that there may be another spot for the serial number on the motor but cannot find it. Any suggestions on the location of serial number on the motor?

 

[usna74]

Re: 650 Merc no spark

I just bought a '69 Glastron with a 650 merc engine. I've been trying to find out more info about getting it into shape. Luckily, I do have the serial number above the transom, but I didn't know it was there because it was so full of grime. I DID find the correct serial number on the engine itself: Take off the top cover, there's a latch above the transome, and on the right side (looking at the engine from the rear) at the top, the same number is stamped into the side.

 

[asm_]

Re: 650 Merc no spark

Like others have said, CDI electronics will be able to supply you with their version of trigger, switch box/coil. The list price for both items will set you back about $650, but I think if you shop around, you may find them for about $450.

With that said, test the component to besure they are actually defective bad. Don't take dealer's word for it. I'd start from the switch box first. Also, be sure to use regular starting battery, not deep cycle. Thunderbolt ignition use battery as primary power source. Charge up the battery before trying to lite the spark plug.

Let me know if yo got any Qs. I just go done reviving a '74 Thunderbolt 850.