04 Mercury 150 v6 2 stroke wont stay running?

[Leandro822]

Hello im new to boating but me and my dad have a little of experience, i have a 04 Mercury 150 v6 2 stroke, a couple weeks ago its been giving me a hard time because it wont stay running, he starts up at 900rmp and sounds great but it slowly goes down until it dies off. I have check all of my plugs and all have spark, also for water in my fuel tank and theres is no water in there, i replace the fuel filter, squeeze bulb, fuel lines, and fuel pump, and still the same problem, but i notice it might have to be something related with fuel, because when he is about to die i choke it and it pops back to 900rpm, i really appreciate all the help you might give me so i THANK YOU ALL.

 

[Sunfish12]

Re: 04 Mercury 150 v6 2 stroke wont stay running?

Yes, it really sounds like dirty carbs, take them off and do a complete disassembly and cleaning.

 

[jeffersondodson561]

Re: 04 Mercury 150 v6 2 stroke wont stay running?

Post serial number?...I would start with checking the fuel pressure at the VST. Pressure should be 41-45 psi and when key is turned off should stabilize after key off and should not drop suddenly.

Is this your motor?

 

[Leandro822]

Re: 04 Mercury 150 v6 2 stroke wont stay running?

My serial number is 0T816469. The above picture is my engine but it not an "EFI", it a 150L Carb. Thank for your comment.

 

[j_martin]

Re: 04 Mercury 150 v6 2 stroke wont stay running?

When it's about to die, try pumping the primer bulb. If that helps, it's either the fuel pump, or a leak in the fuel system somewhere between the pickup in the tank and the fuel pump. If you pump the primer bulb and hold it firmly, and you can't see a leak between the bulb and the fuel pump, then it's before the bulb.

You said you put new parts in it. If they aren't Mercury parts, you didn't fix it.
Buy real parts. We're fixin' problems every day in these big engines that are just inadequate fuel line and primer bulb parts.

 

[Leandro822]

Re: 04 Mercury 150 v6 2 stroke wont stay running?

i buy all of my parts in a local Mercury and Yamaha dealer i have near my home, but ill check my fuel line that comes from my tank and see if there is any leak there, Thank you for reply.

 

[j_martin]

Re: 04 Mercury 150 v6 2 stroke wont stay running?

I got my motor at a discount because the PO's certified mercury mechanic put aftermarket parts on it that weren't adequate. Among them was an aftermarket hose and bulb, proven by scientific measurement (by me) to be inadequate for the job.

 

[Leandro822]

Re: 04 Mercury 150 v6 2 stroke wont stay running?

LOL, i got home today and i went to check out my carbs, i took the air box out and i found a really thick mixture of oil and gas on it and in my carbs i attached it at bottom, i figure that im having to much oil on gas, so i change my check valve and gave it a go and it started right up and he doesn't die, but i went back and checked the line and its half way fill i have a pic below, i dont know if thats ok or not HELP ME hehe, THANK YOU ALL>

 

[j_martin]

Re: 04 Mercury 150 v6 2 stroke wont stay running?

There shouldn't be an air bubble there. There's a bleed screw on the oil pump to let it out.

There is a link to the throttle linkage that adjusts the oil flow amount. There's an alignment mark on the pump linkage to set at idle.

One more thing. A few minutes after you shut down the motor, crack the cap on the oil tank in the boat. There should not be any pressure there. If there is, the check valve on the engine, low, starboard side that feeds pressure to it is bad. It will slowly bleed oil into the fuel system when the engine is shut off and flood it with oil when you start it.

All of this info, by the way, is in the manufacturers service manual. Get one.

 

[Leandro822]

Re: 04 Mercury 150 v6 2 stroke wont stay running?

Yea im gonna get my hands on one of those, could you tell what i have to do in order to get the air out.THANK YOU very much for all your help you have given me.

 

[jeffersondodson561]

Re: 04 Mercury 150 v6 2 stroke wont stay running?

look at the bottom carb, see how their is not oil on the venturi. That line on the carbs goes to the thermal air valve, richens the carb until warmed up. Check thermal air valve?

 

[Faztbullet]

Re: 04 Mercury 150 v6 2 stroke wont stay running?

Check thermal air valve?

good bet....

 

[carholme]

Re: 04 Mercury 150 v6 2 stroke wont stay running?

822;

Here is the service Manual for your s/n:

http://1manual.com/Mercury manuals/Service Manual PDFs/TwoStroke/878079/cover.pdf

Gerry

 

[jeffersondodson561]

Re: 04 Mercury 150 v6 2 stroke wont stay running?

Or if the lack of gas/oil on the bottom carb could be a result of carb being restricted. The bottom carb is usually the worst because all of the fuel in the line gravity feeds down to the bottom carb. If you have a restriction on that carb those 2 cylinders could be in jeopardy. It really takes a trained experienced ear to hear if a cylinder is not hitting just by listening to it, to be honest this is a skill I have not fully developed yet. So you could be running on four cylinders at idle and think it is running on all six.