Help me troubleshoot my fuel problem

bucknutjoe · May 7, 2013

I have a 1983 Four Winns 170 Marquise with a 3.0 Mercruiser 140 straight 4 cylinder. The boat has been sitting, winterized, since the end of the boating season, 2011. I'm trying to get things up and running to enjoy my boat again, but I can't get it started. The engine is turning over, but will not fire. I'm not getting any fuel into my carb. Yes, the gas tank is full and stabilized, it has been all along. Can you guys help me troubleshoot the issue? I don't know where to begin, or what steps to take to look through things like fuel filters, fuel pump, etc.

Thanks so much for all your help!

airshot · May 7, 2013

Re: Help me troubleshoot my fuel problem

These can be difficult to get started at the beginning of each year, if your is anything like my Islander there is a very long fuel line to get to the carb. You should have replaced the fuel filters before starting the beggining of the year and you would have found the lines are empty from evaporation over winter. On my boat I installed a bulb in the line like they use on outboard motors to get the fuel flow up to the pump. Now it takes only minutes to get the fuel up there, wait until you see fuel squirting in the carb before bothering to try starting.
If you fogged the engine in the fall, startup may be even more difficult, I usually remove all plugs and crank the engine over a few times to blow out any excess oil from the fogging, then install new plugs for the season, once I see fuel in the carb it generally starts right up.

Airshot

Silvertip · May 7, 2013

Re: Help me troubleshoot my fuel problem

Choke working? Kill switch lanyard pulled? Remove the flame arrestor and pump the throttle? Fuel squirting into the carb.? Does the engine have spark? How's that for starters.

bucknutjoe · May 7, 2013

Re: Help me troubleshoot my fuel problem

Thanks guys. The choke does seem to be working, kill switch is good. When I remove the flame arrestor there is no fuel. That's what I'm looking for help with. What steps do I follow with the pump and its components?

Bt Doctur · May 7, 2013

Re: Help me troubleshoot my fuel problem

Do you know how to fill the carb fuel bowl?

bucknutjoe · May 7, 2013

Re: Help me troubleshoot my fuel problem

No, other than to guess that you would manually pour some gas into the open top of the carb.

nola mike · May 7, 2013

Re: Help me troubleshoot my fuel problem

That won't fill the bowl, but will get the engine to fire if lack of fuel is the problem.

bucknutjoe · May 8, 2013

Re: Help me troubleshoot my fuel problem

Can someone give me a run-through on the process of changing the fuel filters?

Hoosmatroos · May 8, 2013

Re: Help me troubleshoot my fuel problem

Perhaps your float is stuck. Give your carb bowl a light tap (don't smash it!!) and try to start again. If the float come loose the the bowl will fill by the pump. Pump the throttle and look if fuel comes out.

Is your water separation filter replaced when winterizing your engine? There is a small filter at the entrance of the carb. Just loosen the fuel inlet line and clean the small filter. Check with the fuel line released from the carb if fuel is pumped when you crank the engine (catch fuel with a bootle or so). Open the fuel pump and check for foreign material.

bucknutjoe · May 8, 2013

Re: Help me troubleshoot my fuel problem

If I do open the fuel pump, do I need to have new gaskets or anything to re-seal it, or is it ok to just open it up and put it back together?

airshot · May 8, 2013

Re: Help me troubleshoot my fuel problem

If you open the fuel pump you will need a new filter and gasket. Post your model and serial numbers of engine and outdrive and one of the good folks on here can direct you to the proper mercruiser service manual. All this will be explained and much more....yes you need it !!

Airshot

bucknutjoe · May 9, 2013

Re: Help me troubleshoot my fuel problem

The serial number for my engine is 6338294. I really would like any advice for what exactly to be doing and in what order. Thanks!

dingdongs · May 9, 2013

Re: Help me troubleshoot my fuel problem

do you have a throttle only lever on your shifter.sometimes there is a button in the centre of the shifter so it can be revved without selecting drive.if not put a small amount of fuel straight down the throat of the carb and then try to start it.
don't leave fuel unattended though as its highly flammable.

bucknutjoe · May 9, 2013

Re: Help me troubleshoot my fuel problem

I do have throttle only, and that's how the choke is set, but I can throttle to my hearts content, there's nothing squirting into the carb at all.

bucknutjoe · May 9, 2013

Re: Help me troubleshoot my fuel problem

If I take the fuel line off where it enters the carb and inspect/clean the filter, do I need to do anything to the threads to seal them?

dingdongs · May 9, 2013

Re: Help me troubleshoot my fuel problem

no is the quick answer.you could remove the lift pump from the starboard side of the engine by undoing the 2 screws and see if its lifting the fuel manually from the tank by pumping it with your hand or get a second person to spin the engine over on the starter b4 you remove it.May just require priming by putting some fuel in the pipes initially .be careful if you remove the lift pump as it has to go under the cam lobe to activate it on reassembling.whatever happens you need fuel upto the carb first.

Help me troubleshoot my fuel problem

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