Re: 86 merc 150 xr2
I'm not sure about the fuel lines. They are pretty small to start with so smaller ones could cause a problem. Put the correct lines on to be sure. Did you have to force them on over the nipples?
Even "proper" sized Atwood lines will not supply enough fuel for this engine at WOT.
I fought this bug out of my XR4, and the last step that finally fixed it was to replace the aftermarket fuel line and primer bulb with a Mercury bulb. The aftermarket bayonet connector that had been put in the engine was also inadequate.
If it has the same finger sized filter as the XR4, that plugs up quite easily and shows as fuel starvation at WOT.
Crud floating around in the fuel tank would probably settle to the bottom, allowing clear running early in the day, then get caught in the pickup screen as the day wears on.
The best bet is to find the one last fuel connection that's not used on the carbs, (probably port on the bottom carb) and replace the plug with a barb and temporarily hook up a 10 lb pressure gauge. It needs 2 lbs to run right, can take up to about 7. You'll find that when it craps out, fuel pressure is zero.
You need to get this fixed. Going lean at WOT is about the quickest way I know to make a boat anchor out of that great engine.
hope it helps
John
