2006 Mercury 90hp fourstroke

Aaron Lariscy

Seaman Apprentice
Joined
Apr 23, 2011
Messages
33
Let me start off by saying that I am new to bigger boats and outboards having owned small jon boats all my life so I am learning as I go with this bigger boat. I also have a good understanding of modern day fuel injection having fooled with hot rodding GM LS series motors (GenIII stuff). Anyway here is my issues, I just bought this boat two weeks ago so I am still feeling it out and trying to get it tuned up to my standards as I am very anal about my stuff.

When I brought it home the first time out it had a surging at idle in gear and sometimes when you threw it to WOT it would studder alittle before it took off. I got it home and did alittle investigating and found a vacuum line loose on the top of the manifold that I stuck back on the barb, I also changed the water separator filter (which was full of about a 90/10 mix of water to gas) and replaced the spark plugs.

Now fast foward to this weekend we went out all day friday without a hitch it ran like a sewing machine no surging at idle and cramming it to WOT it jumped up fine all day (6am-4:30pm) and I was tickled with it. We went out again Sunday morning with basically them same story except for my wife kept complaining of a strong fuel smell, no clue if this is related or not because I didn't really smell it myself she has a more sensitive nose.

Now the issues started again Sunday night we went out and it ran fine most of the time when we decided to bring it in I ran it hard back to the landing (1mi maybe) and when I dropped down to idle in gear the surging was back again. Revved it out of gear trying to clean it up but no help really so I pulled up to the dock and let everybody out and shut the motor off for a few seconds. When I went to crank it back up it was unreasonably hard to start (took two tries having to hold the key down to 3-5 seconds each time) I procceded to load it on the trailer still surging and got it on and before I shut it off to pull out the surging cleared out?

Now I am totally lost, I checked to make sure the vacuum line was till attached at the landing and in a moment I am going to dump the water separator out again to make sure it's not full again other than that I am looking for suggestions sorry for such a long post but I feel some background was needed so you could understand where I was. I eventually want to go to the coast with this rig but untill I gain some confidence in this motor I won't be able to without worrying myself to death. :facepalm:
 
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