problems with idle ?? Fuel?? Fuel system??

[BlueeyedRuss]

I have a 4.3 Mercruiser with the carb and alpha stern drive. I took it out of storage, changed oils, lubed things up and let the boat idle for a good while connected to garden hose. Everything seemed fine and the boat ran and idled well. I then took it to the lake for Memorial Day weekend. I noticed immediately off the trailer that the boat didnt seem to want to idle but assumed it was just cold or becuase it had been in storage for a while. Docked it for the night (it was getting late). Next day crank it and it idles fine, but as soon as put it in gear and attempt to accelerate it cuts off. This happens several more times. Eventually I crank it and immediately give it significant gas as soon as its put in gear. The boat takes off and runs great. But as soon as I bring it back down to nuetral, it immediately cuts off, and at this point it does not want to recrank at all. After multiple attempts and pumping the gas many times, it cranks but only runs a few seconds and again the engine dies. I could only keep it running if I pumped the gas several times, cranked it, and immediately put in gear and accelerated (giving it significant gas). While giving it the extra gas,it would run great. But anytime it was taken back to idle it would cut off and be hard to start. This happened through out the day. At the suggestion of a friend, I attempted to adjust the idle. This helped for a short time, ( about 15 mins) then went back to idling low or most often not idling at all. Also tried Carb cleaner at the suggestion of another friend. Immediately after the use, the boat almost did worse and didnt want to crank at all. Later that day it cranked but the idle speed (rpms) would increase then decrease back and forth completely on its own, without me touching anything just setting still in water. I left it alone. The next day I went to load it back on trailer. It still wasnt quite up to normal and did cut off when I put in gear the first time. But it did run much better and continued to idle even after warming up, until I actually cut the engine off. The problem certianly is giving me the impression it is fuel or fuel system related.

Some important factors, I am def not a pro so I am learning as I go, lol. The boat was winterized correctly with on possible exception. The fuel. The fuel tank was filled as suggested by the manual. However it was filled with ethonal containing fuel, Sta-bil was added, under the thought that the gas would be fine with the additive. The Sta-bil may have been added a little heavier than the instruction on the bottle. ( there was already some treated gas in the tank). I have not changed the fuel/water seperator filter yet this year.

So, what can I do to solve the issue. Does it just need the fuel drained and replaced with nonethenol fuel, and change the fuel/water filter, maybe the plugs, ?? or is there more I should do. I know those of you that have been at this a long time will have some good advice. Thanks in advance.

Russell

 

[superbenk]

Check filters including the screen where the fuel line enters the carb. Check timing. Make sure your plugs & wires are in good shape. Consider rebuilding the carb as it might be gunked up inside. Check & clean flame arrestor too.

 

[BlueeyedRuss]

Thanks Superbenk,
What is good for cleaning the flame arrestor. If I remove the fuel line to the carb, will i need anytype of gasket or O ring when I replace it.? I ask becuase there is no marina or boat parts store near by and I will have to order.

 

[chadpcb]

Blue what carb is on that motor.

 

[alldodge]

Thanks Superbenk,
What is good for cleaning the flame arrestor. If I remove the fuel line to the carb, will i need anytype of gasket or O ring when I replace it.? I ask becuase there is no marina or boat parts store near by and I will have to order.

What is the serial number of the motor, or at least the year?

The flame arrestor is best cleaned with diesel or kerosene then use soap and water. You can also use WD40 to break up the crud and then use soap and water. Oil is what is needed to break the crud loose.

Check your shift cable for correct adjustment, if its not right the interrupter switch will kill the motor. Also check the timing and idle rpm

 

[BlueeyedRuss]

Blue what carb is on that motor.

its a two barrel, that all I really know about it

 

[BlueeyedRuss]

What is the serial number of the motor, or at least the year?

The flame arrestor is best cleaned with diesel or kerosene then use soap and water. You can also use WD40 to break up the crud and then use soap and water. Oil is what is needed to break the crud loose.

Check your shift cable for correct adjustment, if its not right the interrupter switch will kill the motor. Also check the timing and idle rpm

its a 2011, not sure what the "shift cable" is, where it is at, or how to check it. not sure how to check the timing either, As for the idle, well that's a big part of the problem, I know it isn't correct but I cant correct it either. It is kinda all over the place, lol usually slow but sometimes it gets fast too.

the flame arrestor, do you just remove the filter portion from the plastic, clean it , then put it back on, or is it cleaned while all still in one piece?

 

[BlueeyedRuss]

Thank you everyone for your help and I will try these as I am very new and all advice is appreciated. But isn't it possible that its just the gas or fuel water separator filter. The engine ran great at the end of last season, no problems with anything, it was winterized and stored about 5 to 6 months and now these problems. Seems it would be something more related to the gas gumming thungs up or having water in the fuel, since I stored with ethanol gas instead of ethanol free gas.

 

[alldodge]

its a 2011, not sure what the "shift cable" is, where it is at, or how to check it. not sure how to check the timing either, As for the idle, well that's a big part of the problem, I know it isn't correct but I cant correct it either. It is kinda all over the place, lol usually slow but sometimes it gets fast too.

the flame arrestor, do you just remove the filter portion from the plastic, clean it , then put it back on, or is it cleaned while all still in one piece?

Being a 2011 model it's a fuel injected engine, the thing that looks like a carb is the throttle body. Remove the arrestor and clean it then also remove the IAC muffler and clean it with soap and water. It is made of foam rubber and be easy when removing and reinstalling.

 

[BlueeyedRuss]

Being a 2011 model it's a fuel injected engine, the thing that looks like a carb is the throttle body. Remove the arrestor and clean it then also remove the IAC muffler and clean it with soap and water. It is made of foam rubber and be easy when removing and reinstalling.

Alldodge,
that diagram isnt my engine. It is a 4.3l 2011, but it is a carburator. It is not the fuel injected version. It is a two barrel carburator
with a round flame arrestor, approx 2 inch thick and approx 8 to 10 inch diameter.

 

[Watermann]

The very best way I've found to clean a flame arrestor is to use Superclean. I hold the arrestor over a bucket and soak it all around with the Superclean and let it sit for about 10 min inside the bucket. Then I use the nozzle on the garden hose to spray it clean inside the bucket. Put the arrestor back in the bucket swish it around and let sit another 10 min, then remove rinse with the hose and let sit to dry. Walmart carries Superclean and I've found it to be the best degreaser for engines and related parts.

Replace your fuel water separator and dump it in a can to see what was trapped inside.

 

[alldodge]

Alldodge,
that diagram isnt my engine. It is a 4.3l 2011, but it is a carburator. It is not the fuel injected version. It is a two barrel carburator
with a round flame arrestor, approx 2 inch thick and approx 8 to 10 inch diameter.

Guess I'm going to need a serial number

 

[BlueeyedRuss]

The very best way I've found to clean a flame arrestor is to use Superclean. I hold the arrestor over a bucket and soak it all around with the Superclean and let it sit for about 10 min inside the bucket. Then I use the nozzle on the garden hose to spray it clean inside the bucket. Put the arrestor back in the bucket swish it around and let sit another 10 min, then remove rinse with the hose and let sit to dry. Walmart carries Superclean and I've found it to be the best degreaser for engines and related parts.

Replace your fuel water separator and dump it in a can to see what was trapped inside.

Thanks waterman, I have some purple stuff, and that def sounds simple enough. And I have already bought the water/fuel seperator, thought it might def need changing and it will be interesting to see what comes out of it. That may explain the problems. Althought changing it is def gonna be interesting as it sets tightly on main hose to the gas tank ( from cap to tank). Probably have to remove the entire mount bracket just to change the filter.

 

[BlueeyedRuss]

Guess I'm going to need a serial number

1A626701