I have a 21' Chris Craft Sea Hawk with a Johnson 150. Its been running great all season, but all of a sudden it won't run above 2500 RPM wide open. If I squeeze the primer ball or if I engage the choke, it takes right off. When I release the choke, the boat slows back down to 2500 RPM. Its idleing a bit higher now. I have a large below deck metal fuel tank, maybe 60 gallons or so. I took off the 90 degree fuel outlet valve and fuel tube to check the check valve. There isn't one...just an open 90 degree fitting which has no obstructions Apparently, the only check valve I have is the one in the primer bulb. Is this enough for a boat of this size? I replaced my fuel lines and primer bulb late last season, but maybe the primer bulb check valve is already going bad. The bulb pumps up hard and doesn't go flat under load. Do they make an inline check valve I can just stick in the fuel line? Or could my problem be something else? I replaced my water seperating filter. The engine gas filter looks clean...it has a large air bubble in it, but it always has. I don't see any gas line kinks, inner gas line delamination, or other gas line obstructions. What's your take on this situation?
Thanks.
Thanks.