50 hp merc rpms cut down sometimes

steplift20 · #1 12-30-2006, 01:24 PM

i have a 1984 50 hp mercury o.b. it runs great but sometimes the rpms cut down like im loosing cylinders and power then it will jump up again and run perfect
i took it to a machanic and after over 400 dollars he replaced the fuel tank and said it wasnt venting right
i only have one switch box but was wondering if it could cause half the cylinders to cut out sometimes?
let me know what you think

macojoe · #2 12-30-2006, 03:29 PM

I just had that problem with my Evinrude and it was the power pack.

Don't know much about merc?? But from asking questions here and trying other things, I figured it out, got a Brand New Power Pack for $50 (new $175)

5 min to change and I was off and running!!

Mine would start fine, take off from the ramp, get maybe 1 mile from the ramp, it was lose power, then it would go then it would stop?
Must have looked like I was pushing and pulling the throttle back and forth.

Then it would just crawl back to the ramp, even at full throttle.

Next time out you could repeat the same. Always good at the start up and down hill from there.

When it first started it would just do it when you were heading out the break water then clear up and was good for the day. then it just started to get worse till it had to be fixed.

I checked the vents, tank, fuel filter, blew air threw all to make sure that everything was clear, and it was.

well Good Luck you will get it!! Just ask and try things!!

I hate going some were to get things fixed!! I think some of these guys know less then we do and just try stuff! And we are the ones that have to flip the bill till they stumble on to the problem!
>:(

steplift20 · #3 12-31-2006, 02:34 PM

your rigth about that but how can i tell if its the power pack i have 4 of them one for each plug or the switch box

macojoe · #4 12-31-2006, 03:10 PM

if you have 4 I believe your looking at the coils, Not the power pack?? But I thought 50 was 3 cyl?

I have a V6 and there are 6 coils and 2 power packs, one for each side.

fallow the wire from th coil to the power pack, thats what powers the coils, you may have just one??

As for testing it, I have no idea how?? I just took a chance with mine, after talking to guys here and my own gut feeling.
I even got the right one the first shot.

macojoe · #5 12-31-2006, 03:20 PM

Here is some from ebay, has a picture of what you need and tells you what it fits.

They have some use from $50 to new at $175. So make your choice.

But make sure you really think its it?? I am just telling you what I had, I am not sure thats what you have.

Check under the fly wheel on top of motor, they have magnets there all around, as the motor turns the Magnets go around the Stator, making power and then to the Power pak, then to the coils, to the plugs.

Do you have the book? That might tell you how to test it??

Go to www.iboats.com and ask there, they are pretty good there also!

Good Luck!! Lets us know what you come up with or if you have any other questions.