50hp merc problem

[mantrapmuskie]

I have a 50hp Mercury 1972 that started acting up last summer. Spark plugs were changed in Spring of 2004. Around the 4th of July the motor had no get-up and go when it was first started. This continued all the way to the end of the season. I take the boat out at least every other week and when I would first start it, it would start up fine just like it always does but when I would pull away from the dock and open up the trottle the engine would only push the boat like I had the trottle open only a fourth of the way or less. I would drive around for maybe five minutes and than all of sudden it would kick in and would run normal. The rest of the weekend the motor would run and start just fine. A week later I'd try it again and the same problem. I changed the plugs again and it ran fine for just that weekend and back to the same old problem. Is this something to do with the gas line or do I have major problem. I hate to take it in if I only have to run some kind of cleaner through the carb????? Any suggestions on do-it-yourself ideas??

[wastewaterguru]

Start by trying the obvious thing of running some seafoam through the carb.

Check the fuel filter and fuel line for obstructions.

It's also possible the fuel pump is bad. This is also an easy fix. ($40 and an hour of your time).

If you don't know how to do basic troubleshooting on your motor, I would highly recommend purchasing a repair manual (Chilton, Haynes, etc.) This will help alot.

[1tofish]

I'm guessing you need a new carb. kit. My 50HP did the same thing it would start great but only had half the power and rpms. After a new carb kit it's ran perfect for 5 years now. The mechanic said I would have possibly have this done every other year, but in my case I haven't. It cost me about $100 to have them gone through.

[marine_man]

I'd agree with the carb kit / going through the carbs as well. It's likely that some of the gas varnished up, plugging the high speed jet temporarily (which was the lag in WOT throttle that you noticed), or something floating in the bowl, plugging the high speed jet from time to time.

However, it could be a weak fuel pump as well... if the fuel pump were weak it could be difficult for the pump to suck the gas up the fuel line, and once you get it primed it works fine for the rest of the weekend...

I'd likely start with the carbs, unless you've had them gone through in the last 3-5 years...

marine_man

[mantrapmuskie]

thanks, I'll give the carb kit a try. I have never changed the carb parts before so hopefully that'll do it. Thanks again.

[efgh]

I have cured more ruff idle , no power, no top end problems with out tearing carbs down with sea foam, just doubble the amount per gal. of fuel and start the motor, my atv cleared up in about 5 miles, my outboard, with the ears on cleared up in 10 mins. this stuff is a darn good first try before tear down.

[mantrapmuskie]

you're right, why tear things apart if a couple of bucks fixes the problem. That'll be first before any carb kit. thanks again I really ap[preciate the inf.