150 Merc Black Max XR2

[eagleclaw19]

I am starting a new topic because I am not sure that the topic out there is the same problem.<br />My merc last year ran great. But this year it does not seem to be doing as well. At Idle it is hard to keep running most of the time, but sometime it kicks up from almost dying to running fine for a short time. When I give it gas while it it trying to die it will die when the load hits it. I have to wait for it to kick out of its "cough" and idle normally to put it into gear and go without dying. When the trottle it down it runs fine. At low RPM's it acts like it wants to die most of the time. and then runs fine the rest of the time<br />Please help<br />Jonathan <br />jldavi19@yahoo.com<br />

 

[dakk1]

Re: 150 Merc Black Max XR2

Jonathan<br /><br />Could be a bunch of stuff. What maintenance have you done lately? Plugs? When was the last time the fuel pump and carbs were rebuilt? Any possibility of contaminated fuel? Does pumping the bulb or choking it make any difference? Is your tach acting up? Has any ignition work been done? What year is it? <br /><br />Dave..

 

[eagleclaw19]

Re: 150 Merc Black Max XR2

New plugs. New fuel filter. 86 Black Max XR2. Nofuel contamination due to the problem remaining after a couple different fill ups. I can put it in neutral and give it gas and it will start acting smoother. If i am running across the lake it is fine. After I slow to an idle it runs fine for about a minute then returns to its sick ways at low throttle or idle.

 

[eagleclaw19]

Re: 150 Merc Black Max XR2

Oh yeah.. I have been told, by a source that doesn't seem to be as knowledgeable as you all on this forum, that it was a needle sticking. I didn't want to put that in the first post to see if some one came up with the same solution. Any thoughts are appreciated.<br />jonathan

 

[eagleclaw19]

Re: 150 Merc Black Max XR2

Don't leave me hanging. Please HELP

 

[dakk1]

Re: 150 Merc Black Max XR2

In the absence of more information, most people would suspect a fuel delivery problem of some sort. Check the simple stuff first. Fuel line assembly icluding the bulb. Vents. Fuel lines at their connections etc. Filling up a couple of times wouldn't necessarily solve a bad fuel issue. I would run it from a clean remote tank to be absolutely sure. You didn't say how long it's been since fuel pump or carbs were rebuilt. Might be time for it. They are easy rebuilds but you'll need a manual if you've never done it. Good investment anyway. Get the Merc manual. Fuel pump and carb kits are relatively cheap. If you decide to DIY get the fuel pump kit with the check valves as there is one without. Same for the carbs, get the full kit. Might as well while your in there. <br /><br />We won't.<br /><br />Dave..

 

[dakk1]

Re: 150 Merc Black Max XR2

Just saw your other post about the "needle sticking". Could be. That's what the carb kits are for. <br /><br />Dave..

 

[ronmold]

Re: 150 Merc Black Max XR2

My '86 175 ran the same way, turned out to be both switchboxes. Replaced with CDI units and motor runs like new. Switchboxes will act up intermitently sometimes working fine, fuel problems seldom appear then go away for awhile.

 

[eagleclaw19]

Re: 150 Merc Black Max XR2

help me undrstand then. if it is not fuel related than why the normal performance at higher throtle? If it was the switchbox than the problem would not disappear with more throttle......wright???