Mercury Blues

[Jeffry Skidmore]

"05 Merc Optimax 225 20ft Bullet. Out fishing today, about halfway thru the day we pulled trolling motor up, started the Big Merc, and out of the blue it just started coughing and sputtering. Wouldn't idle on its own and at half throttle we were making about 6mph. Acted like it was starved for gas but wouldn't take any. WTF???:blink:

 

[Bob Bourget2]

Just out of curiosity...did you prime the bulb before you took off? With the advent of ethanol in our fuel tanks, even brief shut-downs REQUIRE priming the fuel system or you could experience running issues as you describe! Vapor lock is becoming more and more of a problem. Try it as silly as it sounds.....this procedure is applicable to all primer bulb equipped outboards. :blink:

Also....drain and purge the VST {vapor separating tank} and get a fuel sample from it to have a look see.

Other possibilities....fouled spark plug, faulty tps..... Let us know....

 

[TritonGlenn]

Hey Bob, how do you do that drain and purge thing on the VST? Easy to do?

All the best,

Glenn

 

[Bob Bourget2]

On the opti's, port side, there is the "cannister" that the red-capped filter resides in. You'll note there is a u-shaped hose with NO zip-ties attached to either end. Remove ONE end at a time, loosen the allen screw directly next to the hose barb where it came off, and watch the fuel come out. Pour into a suitable container so as to examine it. Pump the bulb a couple of times to "purge" any contaminants. Repeat for the other side. Do NOT over-tighten the allen screws, just snug them up. Clean up any spilled fuel, and wash the inner cowls down with soapy water if you do.

 

[Bob Bourget2]

Obviously...leave the hose on the end you are draining, to make it less of a mess....

 

[Jeffry Skidmore]

Well after getting home and pulling the cowl, it seems that the belt that runs the altenator had broken. Will get a replacement tomorrow. Bob, is it likely that a lower voltage could have compromised the ECU regulating the fuel/air mixture?



Thanks! And I will keep that in mind about priming. We did not prime before starting out this morning, but I did prime during the "episode", but there wasn't any improvment. So if the issue was with the belt affecting the ECU, priming wouldn't have helped. Vapor lock came up in the diagnostic discussion, but was sort of discounted because we hadn't experienced that before.

 

[TritonGlenn]

Thanks. Guess I should have done this when I changed my filter a few weeks back. Now I know. Thanks!

All the best,

Glenn

 

[Jimmy Easterling]

I've had my 200 Opti for almost 2 years now and can remember priming the bulb maybe twice, it has never hesitated to fire right up. I am on the water usually twice a week but: Am I asking for problems later on?

 

[byron cooley]

It ran like crap because that same belt runs the air pump. Before you put the new belt on - turn the alternator, air pump, and tensioner pulleys and replace any that are rough or noisy.

 

[Bob Bourget2]

That'll do it. As stated, be sure to check all of the pulleys, tensioners, and the compressor itself. The belts have just "broken" on occasion though, with no other issues. Clean all debris. The belt should be replaced every other season.

As far as priming the bulb....it's only becoming more important NOW because of the ever-increasing lousy fuel. What was in the past, is not now....PRIME IT!!

 

[Jeffry Skidmore]

Thanx Guys! I'll prime it from here out!