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20 hp merc 200 need help! oil in midsection no power what happened????

R

rob3307

New member
idk what happened but i blew something somewhere and my motors midsection is full of water contaminated oil
13268276_10157009711715714_6413297243104658168_o.jpg
13246174_10157009708875714_1121243699390585404_o.jpg

i damaged the prop on rocks earier in the trip but was still running ok for a few hours afterwards as i worked my way around the lake. on the way back to the car it made a weird noise and bogged down to less than half power, i thought i had either blown piston rings on one cylinder or lost a big chunk of the damaged prop as it vibrated a bit as well. couldn't throttle down or put it in idle without stalling but could restart it with the throttle up.

i pulled the water pump out and impeller looks ok, as do the top gaskets(replaced last year) bottom gasket is a little worn as i didnt change that one and the o ring at the bottom is a bit rough but overall isnt that bad i dont think...

compression in both cylinders is at 125 psi(checked twice)

any help would be greatly appreciated
 
Sounds like it's rung on one cylinder. If so, that explains both problems.

Get it running and yank the plug wires off, one at a time. Be sure to wear insulated gloves and use pliers.

Jeff
 
fastjeff said:
Sounds like it's rung on one cylinder. If so, that explains both problems.

Get it running and yank the plug wires off, one at a time. Be sure to wear insulated gloves and use pliers.

Jeff
Click to expand...

pulled bottom plug and nothing, pulled top plug and motor died and showed me i need better insulated gloves... seems like i lost spark in lower cylinder
 
That's what I thought.

You didn't mention the year of this motor, but IF it has external oils in the back, do this:

First, make a diagram of the coil wiring (or go nuts!) then switch the coils and try again. If the problem follows to the other cylinder, replace the coil. If not...Well; try that first.

Jeff

PS: Seen a lot of coils go bad of late--showing their age.
 
fastjeff said:
That's what I thought.

You didn't mention the year of this motor, but IF it has external oils in the back, do this:

First, make a diagram of the coil wiring (or go nuts!) then switch the coils and try again. If the problem follows to the other cylinder, replace the coil. If not...Well; try that first.

Jeff

PS: Seen a lot of coils go bad of late--showing their age.
Click to expand...

ya i dont know the year... best guess from the merc dealer in my area is somewhere from the 70's based on the serial... thanks for the help, i really appreciate it
 
well i pulled the cover off and took a closer look at the motor, when i touched one of the wires coming out of the switch box it fell apart so i tried wrapping it around the post(didn't work) 13292863_10157019751600714_846674841_n.jpg13282301_10157019752765714_1609520444_n.jpg

Im wondering if i cut the wire at the box where its frayed as well and replace the length of wire13288854_10157019752120714_2086963990_n.jpg if that will possibly fix it... id rather not replace a box the dealer wants $350 for just cause a wire broke on the outside of it...

I took the wires off the coil on the opposite side and swapped them and the dead plug gets spark now so its either the box or the wire
 

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It's the coil. Do a neat job on the frayed wiring, replace the coil, and you should be all set.

Jeff

PS: Good used switch boxes are available on E-Bay for under 100 bucks.
 
You can get a brand new switch box for under 200 brand new aftermarket from CDI 114-6222. That is a pretty common problem with the older mercs the wire insulation is bad.
 
fastjeff said:
It's the coil. Do a neat job on the frayed wiring, replace the coil, and you should be all set.

Jeff

PS: Good used switch boxes are available on E-Bay for under 100 bucks.
Click to expand...

just curious if the coil was bad wouldnt it have still had no spark once i swapped the leads off the good side? once i took off the broken set off and put the good ones on the dead plug had spark again
 
im going to have to replace the wire regardless as i lost about 3 inches of length and it will be shorter once i trim the corroded part off
 
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