'86 Merc 150 questions

[franco802]

Holy crap!! I went through hell this past weekend!! I made plans with a couple of friends to take my new used boat out. Luck Itold them not to wait up for me, because I started the engine and then it died on me!!
I was going nuts!! I finally figured out it had bad gas from sitting last season.
I went balls out and purchased a new 12 gallon fuel tank, fuel line and a new filter and rubber fuel pump. I cleaned the spark plugs, drained the crap gas out of the carbs and cleaned them up with carb cleaner.
I pumped in the new fresh mix/gas from the new tank and it fires right up!! I was having a very frusterated weekend!
The engine now idles but runs a little rough. Might I need to do a carb adjustment? Also, I installed 1/4" fuel line, because that's what was on there. I read the repair manual and it calls for 3/8 or 5/16 (either one). Anyone know anything about this?? Also, it smokes but smells like fuel, typical on a two stroke I think.

[DUCKY]

The crap fuel has probably plugged up the idle circuits. The carbs need to be removed to clean them properly, and that is best left to someone with experience. The carbs on your motor don't really have "adjustments". Once they are synchronized they ahould be left alone. Get into the habit of popping off the fuel line when you put her back on the trailer and let it run itself out of fuel (lower unit still in the water of course). It will save you hundreds of dollars in the future. And yes...Get rid of the 1/4" fuel line. It's too small for a v-6.

[franco802]

The crap fuel has probably plugged up the idle circuits. The carbs need to be removed to clean them properly, and that is best left to someone with experience. The carbs on your motor don't really have "adjustments". Once they are synchronized they ahould be left alone. Get into the habit of popping off the fuel line when you put her back on the trailer and let it run itself out of fuel (lower unit still in the water of course). It will save you hundreds of dollars in the future. And yes...Get rid of the 1/4" fuel line. It's too small for a v-6.
Thank you for the info Ducky.
Also, I noticed when I trim the engine up, I notice fuel coming out of the carbs, dripping down into the cubby part of the stern. Is this just unburned gas/mix that leaks down from the carbs after the engine is shut off?
Wait, that's probably why your telling me to run it dry after use :)

[DUCKY]

Thank you for the info Ducky.
Also, I noticed when I trim the engine up, I notice fuel coming out of the carbs, dripping down into the cubby part of the stern. Is this just unburned gas/mix that leaks down from the carbs after the engine is shut off?
Wait, that's probably why your telling me to run it dry after use :)
That's one of the reasons.... :) That's the fuel in the bowls draining out of the bowl vents. The main reason for running it dry is to prevent varnish buildup in the carbs that plugs up the jets and idle circuits.

[Tom Brown]

The crap fuel has probably plugged up the idle circuits. The carbs need to be removed to clean them properly, and that is best left to someone with experience.
I don't think rebuilding carbs is a particularly big deal. It just requires patience and time. Merc carbs are pretty simple.