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

[passinthru]

Hi all,
Been enjoying tinkering on a motor I resently purchased, I have yet to find a "name plate" on the motor. I did find a plate on the swivel bracket (think that's what its called, right above the clamps) serial number there is "3187154". I haven't been able to cross reference that on anything. Still searching for the other name plate or ways to identify it.
I'm going to attempt to attach some pictures and would greatly appreciate if anyone on here could tell me what I'm missing on the starboard side of my motor. There's two ports that look the same with studs coming out? Not sure if this is something to do with the fuel system or the cooling system?? Been really enjoying learning off hear, lot of great knowledge...Thank you!!!

 

[racerone]

Looks like a 1972 model.----Those 2 locations are for diaphragm , PRESSURE operated fuel pumps.----Do a complete evaluation of this motor before spending any beer tokens.----Post the actual compression values.-----Compression test can be done with a rope on the flywheel.----Will need a new water pump impeller before launching the boat.

 

[passinthru]

 

[passinthru]

Looks like a 1972 model.----Those 2 locations are for diaphragm , PRESSURE operated fuel pumps.----Do a complete evaluation of this motor before spending any beer tokens.----Post the actual compression values.-----Compression test can be done with a rope on the flywheel.----Will need a new water pump impeller before launching the boat.

Thank you for your input, I spent a total of $450 for the 16’ ranger, trailer and motor. Definitely will just walk away from it if it gets to pricey where I couldn’t unload it for close to what I have in it.
While doing the compression test I was not getting any spark. I plan on looking through the wiring starting with the stator and moving on from there. I bought this setup just last week so haven’t messed with it much and not in a huge rush…although my 5 year old is wondering why it isn’t on the water yet My knowledge is little, I’m a industrial electrician by trade but enjoy tinkering and see if I can get her going.

 

[Chris1956]

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.

 

[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.

Definitely a dummy here, I have some pretty knowledgeable co-workers. Was mentioning the no spark and like a moron I didn’t even think about the fact I was just applying 12+ straight to the starter. I’ll definitely have to dive into it more. I do suspect I’ll have to replace spark plugs, cap, miscellaneous wiring. Here in the near future I’ll try and run some Bench tests on what components I can and see if they’re within spec. Thank you

 

[merc850]

Wiring diagram
fuel pump parts the pump originally had brass fittings that the lines attached to (compression type) that are missing from your lines so you'll have to use barb fittings and you'll need the pump body; these people https://www.oldmercs.com/category_s/1702.htm sell the hoses and diaphragm but you'll have to get the pump from Mercury dealer.



replace that black wire that goes from the starter to the front plate it's corroded.

 

[passinthru]

Wiring diagramView attachment 395707
fuel pump parts
View attachment 395708

replace that black wire that goes from the starter to the front plate it's corroded.

Thank you, definitely plan on it. Going to my fuel issue.(just looking ahead for now, thinking out loud) I suspect it could be difficult finding those pumps. Could I just make some blank plates, cap those off and put an electric inline fuel pump? Thanks

 

[racerone]

Should not be hard to find the pump.--Your location ?------Not sure if yours used 2 pumps or just 1------And you might want to test / inspect / clean the distributor cap.-----New one appears to be about $300 beer tokens.

 

[passinthru]

Should not be hard to find the pump.--Your location ?------Not sure if yours used 2 pumps or just 1------And you might want to test / inspect / clean the distributor cap.-----New one appears to be about $300 beer tokens.

Damn!!! Nothing cheap about boating ehh I live down in Arizona…the land of lakes If I had to guess I would think that it used two, just seeing the two areas there missing the pump with the bolts sitting there. Other than that I know zero history about this boat, other than it appears to have been registered back in ‘08 which doesn’t seem all that long ago for a motor from ‘72. Fingers crossed can get the distributor to function properly. I’ll definitely keep everyone posted as I go through it. Not sure I’ll be able to work on it much this weekend but we’ll see.

 

[merc850]

Thank you, definitely plan on it. Going to my fuel issue.(just looking ahead for now, thinking out loud) I suspect it could be difficult finding those pumps. Could I just make some blank plates, cap those off and put an electric inline fuel pump? Thanks

Try John's Old Merc site.

 

[merc850]

I have my 850 runner on a boat and I picked up a poorly maintained one for $200.00 which gave me some useful parts, some marinas keep old ones in the "boneyard".

 

[racerone]

The cowling says 85 but serial # seems to be for a 72 model 80 HP

 

[passinthru]

The cowling says 85 but serial # seems to be for a 72 model 80 HP

 

[passinthru]

I’m not sure if this helps but the shaft says 85hp as well.

 

[merc850]

Correct! serial numbers 3186263 thru 3493912 were 1972 models.

 

[passinthru]

Any chance I could snag parts off a 115?

 

[Chris1956]

Yes, depending on the year of the 115, many parts are interchangeable. IL6 motors before 19791/2 will share ign systems except for distributor caps and disks. They share carbs, (possibly) fuel pumps, fuel/ign linkages, stators, rectifiers, midsections, triple clamps, (possible) PTT units and transom brackets, upper and lower cowls, motor mounts and a whole lot more.

 

[passinthru]

Yes, depending on the year of the 115, many parts are interchangeable. IL6 motors before 19791/2 will share ign systems except for distributor caps and disks. They share carbs, (possibly) fuel pumps, fuel/ign linkages, stators, rectifiers, midsections, triple clamps, (possible) PTT units and transom brackets, upper and lower cowls, motor mounts and a whole lot more.

The guys asking $200 for that motor, says it was supposedly rebuilt years ago and sat. Think he’s had it posted for some time out on the reservation. Could probably offer him $100 if you all thought it was worth it

 

[merc850]

I'm guessing that the fuel pump/wiring harness/ignition can't be used in your motor, go have a look at it if you can with cowling off.
It might be a 1979 model like this one