Mercury 85HP Thunderbolt Ignition Series??? Whats missing??

[racerone]

That 115 appears to be a 1979.----Fuel pump is different.

 

[Chris1956]

Merc850 is likely correct. I do not know if any 1150/1500 had the dual triangle fuel pumps. Some might have. A lot had the single figure 8 fuel pumps. With some transfer covers from the motors with that figure 8 fuel pump, and some creativity, you could probably retrofit it. The ign wiring would likely fit, but OEM harnesses have a history of being shot at this age.

If the parts motor is a later model with ADI ignition, I am not sure you can use it for parts. If it is earlier than 19791/2, and the trigger is good, it might be worthwhile, just for that.

I am worried that your motor with it's good compression, was not fixed by the PO. Why was that?

 

[merc850]

Found this wiring dia. appears that those motors used ADI not a distributor.

 

[Chris1956]

The IL6 motors converted to ADI ignition in mid 1979. The IL4 motors converted to ADI ignition in 1975, if memory serves.

 

[Nordin]

"Blue ribbons" Mercury started in 1972 and your engine is a 80Hp with 85Hp decals. In 1973 they were rated as 85Hp up until 1977, then i 1978 80Hp again.
1972-1975 had battery feed thunderbolt ignition system with a distributor, in 1976 and up they were equipped with ADI ignition.
Master Tech marine can be a good source for parts and check out Mercson at Youtube he works with 4-inline and 6-inline Mercurys.

 

[passinthru]

That motor needs +12VDC on the red and adjacent white wire on the switchbox to have spark. The red wire is hot at all times, the white wire is powered by the ign keyswitch. This presupposes the engine wiring, coil and trigger are good, which is questionable at the age of that motor. Check the distributor wires as this is a known trouble spot.

CDI Electronics used to have a test for the ign system, sans the trigger. Look for the "battery-powered CDI Ignition test" and run it. If the test produces spark, and she has none when cranking, check the carbon electrode under the dist. cap, and continuity of the spark plug wires. The rotor is fragile and non-removeable. You would need to buy a distributor rotor shaft ($200+) to get a new one. The trigger is not replaceable. You would need to buy a distributor body ($250+) to get a new trigger.

You will probably want a service manual for that motor. The Seloc and Clymer manuals are real inaccurate. Check flea bay for a new or used factory one.

Hello all,
Sorry its been so long but finally, finally got around to checking for spark and low and behold she had dang good spark. Thanking my lucky stars there. I need to figure out the ignition as there is no key, may order a new one or just bypass it with a push button or something. But as for now I just put a jumper from the red to the white wire on the switchbox and jumped the started. I sprayed some contact cleaner down the carb and she kicked over right away. Pretty exciting. Next move is getting those pumps ordered, getting some fuel hose/filters and getting the fuel squared away while figuring out/repairing the wiring.
Appreciate your alls input.

 

[jimmbo]

The 72 80hp and the 73 85hp are very different engines. They might have the same Bore and Stroke, but the Induction System is much different. Carb Calibrations would be likely different between the 4 and the 6s
The 1978 and later 80hp engines are not the same as the 72 and earlier 80hp
This Chart is for engine after 1977, so the Jets shown for the 80/85hp from 72 and 73 are likely different, but they wouldn't be the same as the inline 6's Carb's Jets either