Texas Fishing Forum

Rough idle good higher rpm

Posted By: Droyhef

Rough idle good higher rpm - 04/13/17 01:27 PM

Engine is 2005 Yamaha 115hp Tlrd carbed 2 stroke.

Hard to start, will not stay running at low idle. It is running rough at low idle. Pulled all plugs last night, they are wet. Runs fine at higher rpms.
Have to pump fuel bulb and choke every time with neutral idle advanced. Possible it don't need bulb pumped every start but choke and idle for sure. Sat most of winter, I had water in fuel in such this spring. Went though carbs, fuel system etc.

It has new fuel lines, new factory primer bulb, cleaned drained and dried gas tanks, new fuel lift pump last year. New plugs last year.

Where should I look first at resolving this?
Posted By: gary purdy

Re: Rough idle good higher rpm - 04/14/17 11:57 AM

Sounds like you still have a carb that the needle and seat is leaking or the float is not adjusted correctly.
Posted By: crapicat

Re: Rough idle good higher rpm - 04/14/17 01:07 PM

Not a boat repair guy, but over the years when I have this problem, I just throw a few lines over the side of the boat and slow troll some crank baits with the big motor for a tank or so, and it will normally straighten out (not always.) The fast method is to take it good mechanic (who is not stacked up for several weeks) and have the carbs rebuilt. In fact, as a matter of course, I set aside time early in the year to slow troll the big motor so I dont need to take it in for carb work. You can add a can of seafoam in the tank and top off the tank (if you failed to run the tank empty before storing it.) to speed up the process...Hope this information helps.
Posted By: Droyhef

Re: Rough idle good higher rpm - 04/14/17 04:41 PM

Alright I'll pull carbs again, I was suspicious of it being something with them still
Posted By: Droyhef

Re: Rough idle good higher rpm - 04/15/17 02:07 AM

Went through carbs, clean, blow out with compressed air. Started on hose easy, will try with pressure on it tomorrow.
Posted By: texasbassdude

Re: Rough idle good higher rpm - 04/18/17 01:01 PM

How'd it go?
Posted By: Droyhef

Re: Rough idle good higher rpm - 04/18/17 04:15 PM

Seems fine, will run it this evening or tomorrow on lake.
Posted By: Droyhef

Re: Rough idle good higher rpm - 04/20/17 02:07 AM

Ran good at the lake today, started easily. I pulled and cleaned carbs and checked floats, one was out of spec rest ok. I never found anything stopped up but it's running good now so sometging was off in there. Hopefully I'll be able to get back to running trips and fishing this year last two years been full of a lot of big life events.
Posted By: Stump jumper

Re: Rough idle good higher rpm - 04/20/17 04:54 PM

Was the float high? Not sure about Yammies but know my Black Max runs better a little lean rather than rich.
Posted By: Droyhef

Re: Rough idle good higher rpm - 04/21/17 08:45 PM

Yeah, I guess the last time I took them apart I got rough with it? Not really sure but I've checked them before and they were all the same. Nobody else has been in it.
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