120hp Magnapower II Chrysler capacitor and age questions

[chrome dome]

G'day, project motor on a stand has a capacitor tucked in behind the terminal block, a couple of months ago some nitwit...probably me :redface:..disconnected it from the TB and didn't note where it hooked up..now can't remember where it went...it's only long enough to reach the blue ignition, red battery or the orange heat term...l'm pretty sure it ain't that one...anyone help with that?

and what is it supposed to do?

l'm also confused ( no surprises there ) about the donks age...marinshopen says '70-74,
max says '72,
2004 clymer manual says '75-'77 were the years for 120 hp Magnapower II,
not a huge difference l know but has anybody got the correct answer?

model 1207 HD, serial no. 1674,
thanks for any help,
cheers

 

[Frank Acampora]

Re: 120hp Magnapower II Chrysler capacitor and age questions

Is it the capacitor that is about 2 1/2 inches long and 3/4 inch diameter? If it is, then it connects to the red terminal.

However, I don't remember Magna Power II using a separate capacitor. That was used on early ignitions with points distributor and red selenium rectifier. Perhaps the P.O. added it afterward. Are you certain you have Mag II? Chrysler used the term "Magna-Power" quite loosely for a number of different ignition systems. If it is Mag II, all components except the coils will be tucked under the flywheel.

Couple of photos if you have them

 

[fucawi]

Re: 120hp Magnapower II Chrysler capacitor and age questions

It is 1972 from the 1207 HD coding...might help if you need parts to know

 

[Nordin]

Re: 120hp Magnapower II Chrysler capacitor and age questions

Modelnumber 1207 HD is 1972 but MAGII ign. was intruduced in 1974 on 60, 105 and 120Hp. Are you sure you have MAGII ign.?
Something is not correct.

MAGII has everyting except the ign.coils under the flywheel. The electricalparts under the wheel are CD module (1), stator/alternator (1), capacitor (1), regulator/rectifire (1) and triggercolis (4 in this case) one for each cyl. sometimes the rectifire is mounted outside the block and not under the wheel.

CD module have five terminals T1, T4, MB, TAC and MW. MB and MW are the killing circuit, TAC for tachometer. T1 and T4 feeds the capacitor and the triggercoils. A fourcyl. engine has two white/blue wires connected to T1 and one white. White/blue feeds triggercoil for cyl. #1 and #2 and the white is for the capacitor. T4 has also three wires connected, two green for triggercoil for cyl. #3 and #4 and another green for the capacitor.

Pics please then we can help you more.

 

[chrome dome]

Re: 120hp Magnapower II Chrysler capacitor and age questions

thanks for the replies..'we' did down/up load some pics and more info then was about to reply only to have the computer have a meltdown..
so will try again in the morning ( nearly midnight here now ) and l'm knackered LOL

but a quick reply..

Frank..it is roughly the size you mentioned, can't get good access to that side of the motor as it's up against a wall,

it has all the MPII components under the flywheel, 4 coils at the back, nothing on the fuel pump side, has all the connections that nordin posted,

not running at the moment...waiting for new starter motor to arrive from the states,

HAS been re-wired at some stage...has a white going to MB instead of blue..newer connections on TB and other places
has same wiring as the the 105 and 135 MPII models in this manual ( l have 4 Chrysler manuals ) apart from the capacitor


separate running problem...has weak spark on 3 & 4...suspect trigger/CD module problem

thanks for the replies..l'll try and get my wife to try with the pics in the morning,
cheers

 

[Nordin]

Re: 120hp Magnapower II Chrysler capacitor and age questions

Do I understand you right? You have the factorymade capacitor mounted under the wheel and another capacitor outside the wheel on the powerhead. Have never ever seen any MAGII with that setup.
If you have a multimeter with possibility to measure capacitors, measure the white wire connected to T1 and ground. Should be some mikroFarad or 0,5 mikrofarad. Then measure the green wire that goes to the capacitor and ground.
About the same value as the first. Weak spark could be bad CD module but also bad capacitor. Shift capacitorwires at the CD module, connect white to T4 and green to T1 and check if the weak spark moves to #1 and #2.

Franz Marine has new factorymade capacitors, CDI electronics has an aftermarket capacitor but it will be mounted outside the wheel. CD modules are a N/A part, CDI has diconntinued it and even Franz Marine do not have it. Only possibility is to find some working used one.

 

[Frank Acampora]

Re: 120hp Magnapower II Chrysler capacitor and age questions

Perhaps the previous owner had a massive failure and simply substituted a Mag II block onto an older leg. Not knowing better, he kept the capacitor.

At any rate, If your Mag II ignition is failing, the block can be easily converted to Prestolite ignition. If you can find parts, It can also be converted to older distributor Motorola ignition. That is actually the retrofit that Chrysler offered but it is more difficult to install than Prestolite.

 

[Nordin]

Re: 120hp Magnapower II Chrysler capacitor and age questions

Have read through my Chrysler workshopmanuals and yes I found that "large" capacitor you are talking about.
It must be a radio noise suppressant capacitor. In early 1970`s it was only used on 3 and 4 cyl. powerheads equipped with breakerpoints distributers and Motorola regulator/rectifires.
This capacitor does not belong to and effect the ignitionsystem.

Your engine must have been modified with a later 120Hp powerhead with MAGII ign.

 

[chrome dome]

Re: 120hp Magnapower II Chrysler capacitor and age questions

View attachment 121232View attachment 121233View attachment 121234

here's the pics...hopefully
ah, they did work...if you squint and pretend a bit.. LOL..you can just see the capacitor behind the TB..if you follow the loose red wire back its easier to see
thanks for all the help with this, l don't why l didn't think that the power head could have been swapped...obvious when you think about it...

sometimes l can't see the forest for the trees..should change my username to MT Head
LOL
thanks again for all the replies..will keep looking for donor bits n pieces for my son..it's HIS motor actually,
cheers