1980? Merc 9.8

[Strecker25]

Hi all, picked up a new Merc 9.8 tonight for a decent price. SN:5542911

Engine fires up ok in the bucket but has a high idle set, I backed the screw off for idle and at slow idle it sputters and stalls. Started looking at a few things and when testing spark I noticed discrepancy between the two cylinders. Top cylinder only sparks 1-2 times when pulling the cord relatively hard, slow pull it doesnt spark. Lower cylinder sparks 2-3 times consistently even during slow pulls. I swapped the coil wires from one to the other and the problem moves, so both coils seem ok. Also swapped high tension leads, no change

First thing is am I assuming correctly that both coils should spark similarly with a single short pull of the starter? Where should I start looking?

Also, I need plugs and wires. iboats says NGK B9HS-10, and I found the Sierra 18-5228-1 plug wires. Sounds right? Thanks!

 

[racerone]

The wires from the CD unit to the coils , are the cracked / corroded ?

 

[Strecker25]

Wires look pretty healthy. When I swapped them they were nice and plyable and ring terminals looked good. There is a bit of sealant near the CD on the other set of wires that goes up under the flywheel towards the pull starter handle on the forward facing part of the engine but the wires themselves also look healthy.

 

[Strecker25]

Also noticed the plastic piece where the stator wires connect and then the kill switch, cdi, etc also hook up moves around a little bit so it feels like the screws up top might be loose (the piece in this pic, http://www.auctiva.com/hostedimages...897833833&images=897833833&formats=0&format=0)

I'm thinking maybe I need to pull the flywheel and check/clean all connections. Assuming an autozone rental puller can get the flywheel off?

 

[Strecker25]

Update, pulled the flywheel and checked/tightened all connections. Replaced spark plugs and wires as well (plugs were shot)

Same result with what appears to be an intermittent spark when pulling but we had a nice weekend so I put the engine on the back of the dinghy and went for a run. It ran beautifully aside from a seldom miss at idle (it is 40 years old, after all) Starts up pretty easily and makes a ton of power. This is on the back of a 10ft inflatable zodiac with an air floor and it rockets out of the water and up on plane. So, until I have an issue showing itself during running I'll consider this problem fixed.