Me and a few friends were talking the other day about the new CDI/50 amp Marine power Head V's The old standard coil/20 amp one. Most seem to agree that the older ones seemed to have a little more get up and go. It also lead to a very good question. Is HP being lost to run the bigger charging system?

I have a friend that made a 12 volt battery charger out of a briggs 3.5 and a 60 amp truck altenator and it takes all that little engine has to spin that mofo!

My point and question to them was if it take nearly 3.5 hp to spin a 60amp alt how much hp is lost to spin a 50 amp system?

I don't like them !! Everyone I've been in was just not to impressive !!

hol^ neg let me go get my calculator.

Good question... I've been curious too. Do the pros out weigh the cons?

Preston, I havent done any scientific testing but I can tell you that when you rotate a motor with a 20 amp alternator you can simply grab the crankshaft with your bare hand and (with the spark plugs removed) you can easily rotate the motor over, or with just 1 finger on the fan and you can spin the motor pretty easily. On a motor that has the 50 amp charging system you need to clamp a vice grips to the crank and even then it takes one heck of alot of force to get the motor rotate.


Personally I have run the motors (marine and non marine) side by side on identical boats, and the marine motors idle lower and smoother, but top end power (and rpm) is identical. And the only reason I can think of is that there is a spark advance built into the coils, so the motor should develop a little more power on top end.

calculations reads 1.244426...... hp

12 volts running through dropping off 50 amps to the charger=600watts; watts to hp 750W(given standard) divided by 600 watts=1.244 hp

now given 750W=1hp


other factors may contribute as to wire length, thickness, time the charge runs from A to B... yada yada Im not no electrical engineer maybe basinlover can correct me or help me out.

note: the 3hp motors still isnt using its full potential of power to run the charging system bc if it did that mofo wouldn't spin.

I got to run one of the demo engines from briggs when they sent them out and I didn't like it at all. Seemed to lack bottom end and would stall out in veggies while idling.

When my CDI was stock I felt that it was stonger than my old motor. I like them.

I have 1 of each on my boat and use my OLD motor for all my froging/fishing. the CDI runs good it just dosnt have the ass to keep the flywheel turning at 800 rpm

HA! IN YOUR FACE OWEN!

I'm sellin that POS tomorrow.

and besides the advace timing it also has a lighter flywheel to help it spin a little faster with the extra windin's!!!J/s O and u can get the marine motor without the 50 amp charging system 613477-0193-E2

The flywheel on the 50A is lighter holding each in a hand, its noticeable. Once the momentum of the wheel is going I am not sure there is much difference or the timing advance compensates for it. Out of the crate this one ran like a hot 35, 4150 in the water at WOT.

The CDI will idle much smoother at lower RPM and can be set as low as 780 on mine, however starting the motor in thick veggies with no throttle will bog down most motors, even if they are idling at 1000. You can turn the idle up and its still smoother than stock coils at 1000 or 1100