Engine issues

brianluck

Last week ran the boat a bit and my port engine slowly kept dropping Rpm's. thought it was a fuel issue. Yesterday changed fuel filters and port motor wouldn't go above 2500 Rpm's. I changed cap and rotor at the beginning of the year so ill try plugs and wires and see where that gets me. Nothing worse then setting out for a run and she falls on her face..... Break Out Another Thousand lol

mvn

Sounds like lots of people here are having issues like this.  The trick is to get the engine computers scanned for fault codes.

Mark

brianluck

im a 94, no codes to scan. ive got those old fashion carbs! so back to basics. start with what i know it already needs and see what happens

mvn

Ah, the good 'ole days!  I guess just do the usual tune-up stuff liek you say and see how it goes.

Mark

212rowboat

The engine runs, no? Does it run fine up to 2.5k or lug?

Fuel, air, spark..

Coil works low, so it likely works high, too.. rotor button, cap, wires, plugs are likely good, too.. or, good enough that you can look elsewhere first..

Clean the air cleaner/spark arrestor..

Fuel is your 'most' likely issue.. start at the carb.. take cover off, watch plate when throttle is opened... Make sure its got full range.. check to see if there is fuel flow.. make sure your needle valves are unobstructedaand are allowing air...

Also, air out is or can be an issue as backpressure will keep an engine from getting full range of rpm... Check for obstructions... Is it through hub exhaust? Look to see if you picked something up that is lodged in there..

212rowboat

Oh, and I think the thunderbolt ignition can be 'read' by a merc scan tool. Limited codes, though.

brianluck

Thanks drew, yeah she purrs up to and at 2500 but no matter how much throttle that engine won't break 2500 all of a sudden, I'm not dragging anything and didn't wrap anything around my prop.

212rowboat

You may be in need of a new ignition module, then.. I hate to throw parts at something without diagnosing the issue first, as its often expensive and futile all at once.. but you're in luck!! You got one just like it on the starboard side.. it will take you ten minutes to swap modules, and see if the problem follows it to the right side.. :-)

Those connectors worry me, Fwiw.. get some dielectric (sp?) Grease or spray and slap it to those connectors and blades when you do this.

brianluck

awsome drew, yeah id much rather spend a few mintues trying simple things rather then buying parts for the **** of it. next time im at the boat ill give it a whirl. 

n1sniper

drewactual said:

You may be in need of a new ignition module, then.. I hate to throw parts at something without diagnosing the issue first, as its often expensive and futile all at once.. but you're in luck!! You got one just like it on the starboard side.. it will take you ten minutes to swap modules, and see if the problem follows it to the right side.. :-) Those connectors worry me, Fwiw.. get some dielectric (sp?) Grease or spray and slap it to those connectors and blades when you do this.

 

 

where do I purchase this ignition module ? I have a 1994 captiva 209

Cableguy Greg

On my old 232cc with a 5.7L and a Thunderbolt V ignition, the module went bad on it. I replaced it and all was good.

To get one, put your engine serial number into the Mercury Parts Express (Link here) website and get the new part number for the module, then Google the part number.

Dream_Inn

Brian, did you ever figure it out? Always like to hear what the fix is.