Time for carb rebuild? - sat with old fuel for months

[Eddie Mullins]

I finally was able to go get my "new" 1974 boat this Friday. It has a 50 hp 500 Mercury. The boat has been sitting for several months and I now think the fuel system may be gummed up.

It cranks fine, idles good, and at times will throttle up, but not enough to plane off and runs sluggish. At times will die if just eased into gear but if dumped in quickly moving the throttle all the way up will go.

We added carb cleaner to the tank and let it idle for quite a while, then were able to actually get it to throttle up better in gear and ran back and forth on the lake for a while. Ran out the old gas, filled tank with new gas and reapeated and it starting running better, even planed out for just a little while, then back to running rough.

I have a manual for it now, but wondering thoughts on symptoms to you xperts. I am think fuel filtre replacement, card cleaning, possibly rebuild? Maybe even fuel pump?

This will be my 1st out board repair ever. Is this something best left to a shop? I am will to try - any tips, do / don'ts if I do it myself??

 

[hkeiner]

Re: Time for carb rebuild? - sat with old fuel for months

Since the motor is new to you and you probably don't know what maintenance was done on the motor recently, you might consider doing some basic tune up/maintenance stuff before troubleshooting any further.

I suggest the following:
- Clean carbs and set float levels
- Replace fuel filter
- Replace spark plugs
- Rebuild fuel pump
- Peform link and sync
- Check compression