99 25 hp merc

6/15/14 @ 9:13 AM
ORIGINAL POST
BROWNING 1972
BROWNING 1972
USER since 2/10/12
While out fishing yesterday I lost most of my power ran about like a 5 horse. When I finally back after an hour long ride I check for spark and it appear that I'm not getting any spark at the bottom cylinder. Help.
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Displaying 1 to 8 of 8 Posts
6/19/14 @ 8:36 PM
BROWNING 1972
BROWNING 1972
USER since 2/10/12
The coils are fine it the switch box.

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6/17/14 @ 2:47 PM
scrub
scrub
USER since 8/15/06
Coil

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6/16/14 @ 9:00 PM
BROWNING 1972
BROWNING 1972
USER since 2/10/12
Cdi? Are you talking about the coil or switch box?

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6/16/14 @ 8:46 PM
scrub
scrub
USER since 8/15/06
You have ruled the plug out. Now move on to the wire. After that the cdi if its not the wite

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6/16/14 @ 7:50 PM
eyesman
eyesman
USER since 1/7/02
I have a 99 25HP Mercury. Last spring I too had the loss of power. Mechanic tore it down, the rings in one cylinder had seized and lost most of the compression in that cylinder. The piston pitted and scored the cylinder wall. A new power head was just short of $1,400.00. Mechanic said an alternative would be to hone the cylinders and put in new pistons at considerable less cost, somewhat of a shot in the dark but worth a try. Motor does run and has reasonable power. It does lack full compression on that one cylinder and has a noticeable rattle when under power. Made it through spring walleye fishing so far, will see how long it does last. The motor was a lemon from day one with plenty of shop time previous to this problem.

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6/15/14 @ 12:24 PM
BROWNING 1972
BROWNING 1972
USER since 2/10/12
I switched the plugs around and no spark to the bottom cylinder.

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6/15/14 @ 11:05 AM
thdrduck
thdrduck
USER since 4/16/11
It could be that the coil for that jug is bad. I have had the insulation crack over time leading to a dead short to ground. You need to take the coil off and look at the bottom of it to check for this. If one is cracked the other is probably cracked too. Other things to check would be points and plug. You should be able to get to the points without removing the flywheel.

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