Number 3 cyl low on power

[Keith Buchanan]

Hi Guys.<br /><br />Been a while since I have had any problems but here goes.. 1989 50HP 3Cyl.<br /><br />Started loosing power on number 3.This problem is intermitent in the fact that it will surge at full power for a brief second or two then bog down. Swapped over coils no change, swapped over input to switch box no change still weak combustion on this cylinder. Compression test good, carbs cleaned, reeds intact.Recent pump diaphrams, new high tension leads plugs etc,etc. My attention is now been drawn to the trigger or timing. Any pointers before I pull the red stator off.<br /><br />Regards all...Keith B.....

 

[outboard tech]

Re: Number 3 cyl low on power

89 3cyl 50HP? If this is a 3cyl with 2 carb setup, you could still have a fuel problem with the bottom carb, because the top carb will supply 1, and 2. Try pushing in the key at high throttle (on the water, under load, that is) for a second. If it picks up that cly, your problem is fuel delivery. As for swapping primary leads to/from switchboxes, perhaps an inductive timing light on the secondary wires (coils to plugs) would be a better indicator of ignition failure on a particular cly. Outboard high tension leads will outlive you and I most of the time and so will the ignition coils. I think I've seen maybe one red stator failure since they came out--all that said, intermittant powerloss could be fuel or igniton, but probably not piston failure, since you say it will fire occassionaly.

 

[outboard tech]

Re: Number 3 cyl low on power

I forgot to add, if the problem is fuel, related to that bottom carb, and it occassional fires #3, I'd be checking for some water in the fuel. It's heavier than gas, and tends to be found in the lower carbs on outboards. Your #3 sparkplug, will look brand new if water is involved--also try swapping some plugs, cly to cyl.(Use the plugs in the motor, not new ones)If you have one fouled, the problem will follow the spark plug.

 

[Keith Buchanan]

Re: Number 3 cyl low on power

Thanks for the reply Ben. Water in fuel is definately not an issue nor is it the carbs as these have been cleaned and substituted for known good carbs. Pushing the choke floods the cylinders and I get an immediate power loss. Yes the bottom plug is considerably cleaner than the others but this I put down to unburned fuel. Swapped plugs around still the same. I concur with your suggestion of an inductive timing light that would be the next logical step before lifting the stator.<br /><br />Any other suggestions appreciated.<br /><br />Regards Keith B...