50hp bogging down at WOT and will not idle

[gerrym]

Just purchased a used 15 foot Bayliner with an ‘88 50hp Force. No problem starting. It doesn’t idle real well and when I run WOT it is very weak…feels like it is bogged down. Every so often it kicks in, but only for a split second. The bulb is soft at WOT, but a little stiffer at idle, but never completely hard. I noticed today that the fuel tank, which is plastic, actually collapses slightly during operation and when I took the cap off it definitely had a seal. I have decarbed with Seafoam Deep Creep and changed the plugs as many on the forum have suggested, but no change. How do you think I should proceed?

 

[roscoe]

Re: 50hp bogging down at WOT and will not idle

You must open the vent on the fuel tank during operation. It cannot be sealed. It is restricting the fuel flow to the engine.

Check both spark plugs for a good strong spark.
Sounds like only one spark plug is firing most of the time.

 

[gerrym]

Re: 50hp bogging down at WOT and will not idle

Thanks, I was not aware the vent needs to be open on the tank. Have not owned an outboard before so I am open to any help I can get. I'll check the spark and let you know how it goes.

 

[gerrym]

Re: 50hp bogging down at WOT and will not idle

roscoe, You were right on the money. Only the top spark plug is firing. I'm amazed that it runs with only one. I'm excited to see what happens when it is firing on both!
Any suggestions on tracking down the problem? I have the manual on order, but it sounds like you guys on this forum really know these engines from experience. Any help you can give would be greatly appreciated. Ger

 

[roscoe]

Re: 50hp bogging down at WOT and will not idle

Check over all the wiring, looking for breaks in the insulation, loose connections, corrosion.

Then test the coil resistance. Not sure what the number is off hand, don't have manual with me.

Next would be the cd module and trigger.

Before spending any amount of $ on the motor, you should check the compression to make sure it is good.

 

[gerrym]

Re: 50hp bogging down at WOT and will not idle

Well, I thought I was on to something. I swapped the ignition coils and the one that didn't have spark worked and the one that did originally have spark did not. Then I removed the panel to look for possible loose wires or bad connections...did not find any. put it back together, tried it and no spark on either. Frustrating!
Heading out of town for a couple of days and this is going to drive me crazy.
Don't know what I did to go backwards, but I will keep at it.