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1970 merc 7.5hp phase maker troubles..blowing coils

R

roonie

New member
I picked up this sweet little engine in palm springs ...its litterally like new. It has 100lb comp. both cyl. If you seen this engine in person your first word would be ...WOW....thats how clean and new she loooks..but i guess looks can be deceiving...lol
I bought the engine for $100 as it had bad wires leading from the stator and the top plasticof the stator was litterally blown off. The stop button was probably used with muffs which seems to be a common problem with these phase makers.
I purchased a used 1971 7.5hp and swapped the coils and stator and got the thing running.
it ran great for a bit then seemed to drop one cyl. ...no spark. I swapped wires and found the lower cyl to not be firing.
Ive since bought two orange coils and tested them ...they tested at just under 1000ohms. and i had a ton of spark.
took the boat out and soon after running well, she dropped the same coil.
Brought the engine into the shop today..tested the coil..it now has 0 ohms. and i have no spark on either coil although the top coil has 988 ohms. I took of the flywheel to look at the points. they did look a bit dirty so i cleaned the points and reset at .20 and yes i do realize they spark on closing.
Im fairly good at things like this but now im stummped...could it be the stop button shorting? I have visually checked it. I would like to disconnect if someone can help with that as well as why it keeps blowing the same coil/s
Again..the used stator was bench tested by starting the parts engine before removal. Ideas anyone? thanks in advance
 
The stop button on those works assbackwards--it opens the circuit to kill the motor.

You want to ground the kill wire to the block and never use that stop button again--that's what murders Phase Makers, opening the circuit when they are running. (The single cylinder motors were set up that way and have been far more reliable.) You can choke it to kill it, or set the idle speed a bit too low.

Try that and get back to us.

Jeff

PS: Find a nice, bright metal ground.
 
fastjeff said:
The stop button on those works assbackwards--it opens the circuit to kill the motor.

You want to ground the kill wire to the block and never use that stop button again--that's what murders Phase Makers, opening the circuit when they are running. (The single cylinder motors were set up that way and have been far more reliable.) You can choke it to kill it, or set the idle speed a bit too low.

Try that and get back to us.

Jeff

PS: Find a nice, bright metal ground.
Click to expand...
so you think this stop button is the reason i keep blowing the one coil? i knew long before i used the engine, not to ever use the stop button on these engines so im not sure this is the problem. there are two wires coming from that stop button...also what do i do with the salmon coloured wire that goes from stator to stop button?leave it on that plastic block?

 
Right. The salmon colored wire coming from the assembly beneath the flywheel.

Be sure the metal is bare where you ground it--no paint allowed.

Jff
 
k...thanks..talked with a guy from tech support at CDI. He thinks its some sort of a short perhaps in the points. Says to pull flywheel and reinspect white insulator blocks....they look brand new but i will recheck them.
 
the engine originally had the green coils...ive replaced with orange...both those coloured coils blew (only bottom cyl. coil) ive read about all this and talked with CDI about these coils.....black and blue coils are the only coils not allowed...thanks anyway flyingscott..hey are you also on 3wheeler world website?
 
I put the phelon magneto plate, cam and flywheel on my 1973 7.5 and she runs like a charm just look for a pre69 9.8 parts motor and dump the phasemaker.
 
kimcrwbr1 said:
I put the phelon magneto plate, cam and flywheel on my 1973 7.5 and she runs like a charm just look for a pre69 9.8 parts motor and dump the phasemaker.
Click to expand...
funny...i do in fact have a 1964ish 9.8hp....you mean they will in fact interchange? i have been told once fixed...the phasemaker can be dependable engine
 
The phelon magneto ignition is much more dependable and considerably cheaper to maintain in my opinion. which stator do you have the earlier phasemaker or the later one with the red module? The red one requires the green coils. No matter which one you have the throttle pickup adjustment is the most important. Just a little bit off and you will allways be stuck in the hole. If you put the phelon ignition in use the .020 point gap and the .025 plug gap. The throttle pickup is adjustable after 1970 so just put it in forward gear and give it WOT then check the throttle pickup has about 1/32 inch clearance from the cam when you push the butterfly fully open with your finger. You dont want the link to bind up at WOT it will wear out the shaft in the carb. If your running surface gap plugs try the champion J6Js set at .025 for the phelon and .030 for the phasemaker.
 
Oh yea if you swap the ignition be sure and mark the flywheel and cam with a felt marker so you do not get them mixed up. Does the older motor have good wires and a kill switch. You can allways choke it to kill the motor it just makes restarts more difficult when you flood it.
 
kimcrwbr1.....thanks for this. If you read my post in entirety you will read that i bought this engine with blown coils and stator. The original stator had a green plastic top...the coils were brown. I purchased a 1971 7.5 parts engine and swapped out the ign. with green coils and black plastic top stator. It ran great for an hr. on the water then slowly i began to loose the bottom cyl. spark.
fast forward..i got two used orange coils that tested 1000ohms....the engine ran well for about 10 min. then dropped that same cyl. coil..its dead...reads nothing. Im thinking its got to be a direct short of the white plastic point blocks but have to check them. This engine is virtually new (1970) in cond. someone previous to me obviously used the stop button incorrectly.
How sure are you that my old 1960s 9.8 will swap out? im really thinking i would like to remove the stop button for now and change the plastic blocks and i should have no further problems with this engine as like i stated...the rest is like new. I have read that these engines are dependable for many years once repaired.
If you read any manual from CDI or wherever...it states to never use the kill switch on these engines as you will in fact blow the ign system. Can i hear other opinions on switching the complete ign system over to the older mag system so i can further make a decision. thanks
 
The 1960 engine has a Phelon mag--a MUCH better set up! It will interchange and work--I've done several--but you need to change ALL the parts, especially the point cam. Sometimes you have to rig up the linkage that moves the mag plate--some of these motors had a different throttle arrangement.

All and all, a worthwhile swap; and these are great running little motors.

Jeff
 
ok...you sound pretty confident.....yes i have that wavy washer.what #6 and #7 are you refering to. sorry but im not up oin my boat engine lingo...lol
 
i think you will agree..nothing wrong with the white plastic blocks. I would like to keep the system the way it is and NOT get rid of the phaze maker for now. Does anyone know what to do with this black wire from stator now that ive disconnected the salmon colored wire and grounded it? And...does anyone have a stator tester diagram as ive only found one from CDI but its for 1972-73 phasemaker...mine being 1970.thanks so much thus far...really appreciate the help....the river walleye will have to wait a bit more.




 
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There is no way to accurately test the stator with a multimeter. It is a hybrid between a CD ignition and a magneto type and good luck on finding a new stator. It is a roll of the dice finding a good used one also your likely buying someone elses headache. The red module can be tested it is just a series of diodes to process the two coils one slow speed and the other is high speed but you need all components working good for a dependable ignition. You need good wires, stator coils, condenser, ignition coils, plug wires, points. Your stator has the condenser built into it the only way to test it is with a spark gap tester. You can test the ignition coils and make sure the points are good and the wiring is correct and good. If everything checks out your stator is likely bad if you fail the spark gap test but is it cost effective to chance buying a used stator?
http://www.maxrules.com/oldmercs/Wiring/1966ona/img012.jpg
The black wire goes to engine ground and I believe you break the salmon wire to kill the motor. Do you get spark if you ground both the black and salmon wires?
 
Does the black wire from the stator go to the points plate and then down to the engine block? Thats what it looks like in the diagram possibly the points are not getting a good ground and isolate the salmon wire.
 
ive always got spark on the top cyl....its weird though because sometimes i loose spark on both until i do some tinkering...then it seems i get spark back on the top cyl. again. I put a new coil on bottom cyl coil and both work until i hit the water ...then soon after i loose bottom cyl. again. Does sound like bad stator doesnt it.
The black wire from stator goes straight to the ground on case right next to stop button. i have both stator wires grounded now...made no difference.
 
If im going to swap out the phase maker i sure hope someone on here will be here to help. Ive helped build a couple stock cars...my dad was a stock car racer...... but boats...thats another story...lol
 
If im going to swap out the phase maker i sure hope someone on here will be here to help. Ive helped build a couple stock cars...my dad was a stock car racer...... but boats...thats another story...lol

found this good read





[COLOR=#9D9D9D !important]From:
<[email protected]>
[COLOR=#9D9D9D !important]Subject:
7.5hp phase maker learnings
[COLOR=#9D9D9D !important]Sent date:[/COLOR]06/19/2016 01:32:29 PM
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http://forums.iboats.com/forum/engine-repair-and-maintenance/mercury-mariner-outboards/10127177-1971-mercury-7-5-phase-maker-learnings
 
Is there a braided wire on the bottom of the ignition coils? Try pigtailing them together and and solder a ground wire and solder a lug terminal so both coils get a good solid ground. Here you see the ground wire from the factory it was just sandwiched to the bracket and after the years corrosion can keep it from grounding properly. Not sure if it applys for your coils tho just working off memory it has been about 8 years since I worked on that style ignition.
http://www.ebay.com/itm/Used-Mercur...ash=item3f63b1de61:g:4tkAAOSwagdXR2FN&vxp=mtr
 
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