New to mercury - 1970 115 HP

[INDYCAVER1]

Hi, I picked up a new to me motor this week. It is a 1970 115 mercury thunderbolt ignition. I didnt know much about mercs because now i run a johnson, so I didnt know much about what to look for. Now that I have it home I noticed that the distributor says motorcraft on it. Im assuming that is probably a bad thing. The motor did run when I went to pick it up though. Has anyone everseen someone retro fit a auto distributor on one of these.? I could tell that the factory coil is disconnected and a new different one has been installed also. Any thoughts or opinions would be great. Do i need to try to find all original parts?

 

[Moody Blue]

Re: New to mercury - 1970 115 HP

The incentive to swap out the "Merc" dist cap with an automotive one is cost. If you are able to find a new Merc dist cap, it's going to set you back about $150.

Lots of old Merc owners would be interested in how that Motorcraft cap was retrofitted .

 

[INDYCAVER1]

Re: New to mercury - 1970 115 HP

actually it is stamped with motorcraft on the base of the distributor itself. Not just the cap. I also noticed just a little bit of grinding on the middle carb to get the distributor to clear. Ill try to post some pics. I could be wrong, but it really looks like the whole distributor base and cap have been swapped.

 

[daveswaves]

Re: New to mercury - 1970 115 HP

actually it is stamped with motorcraft on the base of the distributor itself. Not just the cap. I also noticed just a little bit of grinding on the middle carb to get the distributor to clear. Ill try to post some pics. I could be wrong, but it really looks like the whole distributor base and cap have been swapped.

Yes, please do post some pics. A distributor swap is good info.

 

[INDYCAVER1]

Re: New to mercury - 1970 115 HP

Here are a couple pics. The more I look at it the more I see. It seems to have been clamped onto the old base to hold it in there. I really wish i would have seen what a factory one looked like before I saw this one. The funny thing is that it worked. and it ran and started with ease and idled smooth. Look at the pics and let me know how much I screwed up. Any chance I would be able to find the whole factory distributor somewhere. I might just see how it does with this one though.

 

[INDYCAVER1]

Re: New to mercury - 1970 115 HP

Anyone have any suggestions on where the best place would be to find one. Im gonna try here locally on monday, but if there is a good site for used parts on the net you know about, id like to know it. From what ive found the whole distributor is NLA.

 

[AllAboard]

Re: New to mercury - 1970 115 HP

Where in Indiana are you? The only boat salvage that I know of in Indiana is INDY BOAT SALVAGE. A used distributor will set you back $250 though. You can try ebay, might get lucky.

 

[INDYCAVER1]

Re: New to mercury - 1970 115 HP

Im near indianapolis. The boat salvage isnt far from me. I planned on calling them when they open on monday to see if they have one. What do you guys think about what i have goin on now? I actually cant believe it runs. I dont know what it will do under load though. Its hard to judge how a motor runs on muffs, but not in the water. Given the price I paid for the motor, I could afford to spend a little money getting it in good shape. I wish someone lived close enough to come look at this thing and tell me what they think. I think it is pretty innovative what they tried to do with it. Im suprised someone doesnt try to make parts for some of the older models like this.

 

[buzzm19]

Re: New to mercury - 1970 115 HP

It looks like someone changed it over to the point system, as I noticed no wires from your spark box (the three terminals to the left of dist are not used) which are needed in the stock form. If it has points I would stay with them (simple system). I have a 1978 115hp with electronics and what a nightmare I am having. I would appreciate any info on that dist as I would love to change mine over to points, and believe me electronics won't make the motor run any better. I do know the older mercks ran points, but on yours why the spark box? Buz

 

[turtles11756]

Re: New to mercury - 1970 115 HP

test compression ? run it the way it is , get the parts manual at oldmercs.com and take your time the original will turn up on ebay and you won't need more than $75.00

 

[INDYCAVER1]

Re: New to mercury - 1970 115 HP

Does anyone what what other years or sizes motors would have the same distributor for a 70 115 thunderbolt. I have been having a little trouble finding info on the thunderbolt ignition and how many years they used it.

 

[Moody Blue]

Re: New to mercury - 1970 115 HP

Not certain but I think any inline 6 model from 1970 thru 1976 or so would use the same distributor. Even the inline 4's used the same distrib with the exception of the trigger plate and cap. The four's had 4 slots in the plate and 4 wire cap while the six's had a 6 slot plate and 6 wire cap.

Others will probably know for sure.

 

[INDYCAVER1]

Re: New to mercury - 1970 115 HP

Ok, thanks for the help. If I find something close Ill post it on here and see if you guys think it will work. Theres an old boat at my grandpas campground that I dont think has moved for years with a 4 cyl 85 hp. Maybe I can get the distributor off that and by a new cap and trigger. Or I might find one on ebay. the boat salvage in town want 250 for one and I think thats too much.

 

[olefisherman]

Re: New to mercury - 1970 115 HP

i had a 1954 merc 40 hp it had a magneto ignition and a distributer . a tune up was a full day of tinkery . the mag spark had to be synchronized with the dist . but when it was right it was killer spark . the mag was the same as on ford tractors. if they have sucesfuilly replaced the factory stuff with batt coil and dist type ignitiion i think i would just run it . it should be easy to tune and find parts for.

 

[Droll]

Re: New to mercury - 1970 115 HP

A used distributor will set you back $250 though.

NOT a bad prize for a GOOD inline 6 distributor... an aftermarket rotor/shaft are $270..A Distributor Cap are $163 ..

I actually cant believe it runs. I dont know what it will do under load though.

If that DIY distributor ARE from a car ( 4-stroke ) it will only have ONE point... so at over 3000 rpm the the dwell time will be to short to give a good strong spark ( older Mercury distributor used TWO points AND TWO coils ) ...

Im suprised someone doesnt try to make parts for some of the older models like this.

Well they do
CDI electronics (.com ) makes replacement part for this type of distributors ( NOT a complete unit, as you will need the original shell .. )

Does anyone what what other years or sizes motors would have the same distributor for a 70 115 thunderbolt.

Any distributor from any inline 6 produced from 1970 and up to mid 1979 will fit ( direct bolt on ).
Distributors from the inline 4 engines will fit too but you will need the dist. cap and trigger disk from an inline 6 engine.

If it has points I would stay with them (simple system).

Simple design... but but a paint in the *** (* = obliviously to bad a word for Iboat to accept ) as to adjust properly ( sync TWO points.. does require special tools as a simple feeler blade will NOT be accurate enough, ( Dwell gauge are needed )...

I have a 1978 115hp with electronics and what a nightmare I am having. I would appreciate any info on that dist as I would love to change mine over to points,

Then why not just fix it ?? a good working Thunderbolt ignition are way better than the old dual point/coil system...

OR you could modify the engine to use the later ( mid 79 > ) CDI ignition system ??, some DIY skills are needed but it can be done...

I would stay with the original ignition system IF it was my engine, possible upgrade to the trigger/switch-box/coil from CDI-electronics ?

I do know the older mercks ran points, but on yours why the spark box? Buz

Mercury stopped using points back in 67 ?, his engine came with an electric Thunderbolt ignition, Mercury came with the SS ignition in 68 ? ( SS ? Solid State ) later renamed to Thunderbolt...



Arne Kjetil

 

[mke039]

Re: New to mercury - 1970 115 HP

Hi,
I was reading your posts. I have a couple of these inline 6's that I mixed and matched to get a working engine (just had it out yesterday on the Mako).
They are decent engines, lots of power. I have a bunch of spare parts for it too. Let me know what you need, maybe I can unload some of this stuff.

Do you have a tilt trim on this engine? I know some of them didn't have them, and they are necessary! Especialy if you want to beach the boat anywhere. I have a bunch of this stuff too.

 

[INDYCAVER1]

Re: New to mercury - 1970 115 HP

Good Im glad alot of different years are the same so I have a wider range to get one. I know I need a coil too, cause the old one has the lead cut off. The only thing is I think Im gettting a free boat with an I/O so the merc by be on hold for a little bit but I still plan on getting it running.

 

[INDYCAVER1]

Re: New to mercury - 1970 115 HP

Its a no go on the free boat. It needed too much work and engine had water in the oil. It might have been ok if the motor was good but id have too much in it to get it water ready. So as soon as a save my lunch $$ for a while Ill be getting parts and working on the Merc.