I bought a boat it has a nice outboard, and ran great the first time out. The problem is it doesn't like to idle. Has electric start so it's not a huge deal, but at low speeds can be a pain. I looked at primer bulb and it has some cracks, not thru it, but looks like it should be replaced. I looked at this because it always seemed to idle OK if I always primed it, bulb was usually soft. I am not sure if there is a simple idle adjustment. Not sure where I can get a manual for this motor but would love one. Anyhow any thoughts would be nice, Thanks in advance.
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1997 Merc tracker 25 HP
- Thread starter mongo36
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Primer bulb could be bad or you have a fuel pump going.Replace primer bulb first than try it & if primer is still soft when ideling I'd look into fuel pump rebuild.
ben2go
Well-known member
Sounds like it sucking air into the fuel line.Check your connectors,and primer bulb.
wasilvers
Well-known member
Does it not idle at 'idle'/neutrual or not idle under 1500 rps? I guess the question is, at what rpm does it keep running? If the fuel lines do not solve the issue and the engine is just running to slow to stay running (avg idle is 600 - 800 rpms) you might just adjust the idle speed. I adjusted this down on my new-to-me engine because they had it idling at 1000+ rpms. I set it at 600 rpms which turns out is a little low because after long runs, it doesn't like to stay running all the time, but that's just cause she's all warmed up 
Good luck,
Will
Good luck,
Will
Thanks for all your inputs. Just to let you know what I have done. I replace the fuel line from the tank to the motor. It didn't solve the idle problem. It idles OK until you put it into gear, then dies, unless you really gun it then it's fine, or after a long run then when you come down to idle, it dies.
I am sure this will give you guys a big clue as to the problem. Today i took it up a fiver, it ran fine for 30 minutes up, about 6 miles. When we got to where we were going it dies, and DIDN'T restart. we used a trolling motor and 2 batteries to get back down the river ( Very long trip). Anyhow, It turns over, it has spark, I can see fuel to the filter ( I pulled it off and watched it fill back up). But no start. I pulled the small fuel lines off that go up the side of the motor to the combustion chamber and cranked the motor, got a very small amount of fuel out, like spitting. I am hoping you will agree it's the fuel pump causing all my problems. It's an easy repair. I don't know because I don't know how much fuel should be coming out of those lines. Thanks all in advance.
I am sure this will give you guys a big clue as to the problem. Today i took it up a fiver, it ran fine for 30 minutes up, about 6 miles. When we got to where we were going it dies, and DIDN'T restart. we used a trolling motor and 2 batteries to get back down the river ( Very long trip). Anyhow, It turns over, it has spark, I can see fuel to the filter ( I pulled it off and watched it fill back up). But no start. I pulled the small fuel lines off that go up the side of the motor to the combustion chamber and cranked the motor, got a very small amount of fuel out, like spitting. I am hoping you will agree it's the fuel pump causing all my problems. It's an easy repair. I don't know because I don't know how much fuel should be coming out of those lines. Thanks all in advance.
Sounds like fuel pump.When motor dies you should check to see if primer bulb is hard or soft.If soft probably fuel pump.Easy fix.
ben2go
Well-known member
mongo36 said:
This sounds like an ignition problem.Pull the plugs,lay them against the head, and crank the engine.The plugs should spark bright blue.
Take cowl off motor when it doesn't start & have some way to shoot a little pre mix into carb to see if its a fuel issue.One of those pump oil cans is what I use to trouble shoot.Just a half a squirt,don't need much.Than try.If you get fire possible you have a little piece of dirt by the needle & seat or another blockage somewhere.
Yes,but very little, teaspoon or less.If its a fuel issue it should pop.Make sure to have your throttle cracked a little so it doesn't just bounce off the throttle plate.
I'm starting to agree with ben2go,it being electrical.Even though it has spark it is still an electrical problem.I had the same problem with my 25 Merc(Same motor)If memory serves it was the stator but didn't find that out until I replaced everything.They have ways to test your electrical components but that don't always test out as was in my case.I race the 25s & even at the race they where not able to pin point the problem.We chased it as you are,but it did end up being electrical.It probably isn't your coils.Either stator or switch box.I will see if I can locate the test for each but remember that don't always tell the truth.Send me a private pm.
ben2go
Well-known member
You can run a resistance test on a stator and it come up good and still be a bad unit.I would do(or have done) a compression test on the engine to make sure it isn't low on compression.If that checks out I would rebuild the ignition system.
If your stator has been replaced than it could be your trigger.I will try to find the test for the stator & trigger.
I found the tests in my Merc book & it is quite long.I copied it but I don't think I can post it here.
Testing Trigger.
Disconnect trigger leads from switch box(make sure to label them where they go)
Test leads to......
Between trigger leads (brown/yellow & brown/white)
resistance (ohms) 650-850
note: above resistance readings is for a cold engine(room temp)Resistance will increase if engine is warm
___________________________________________________________________________________________________
Ignition coil
disconnect wire(s) from coil terminal(s)
remove the spark plug leads from coil tower
test leads to
between (+) & (-) coil terminals
resistance (ohms) .02-.04
between coil tower & (-) coil terminal terminal 800-1100
Remember that just because they test good doesn't mean they are.(I know sort of messed up but that's the way this electronics stuff is.
If you where closer I'd let you test with the extra components that I have.
Good luck
Testing Trigger.
Disconnect trigger leads from switch box(make sure to label them where they go)
Test leads to......
Between trigger leads (brown/yellow & brown/white)
resistance (ohms) 650-850
note: above resistance readings is for a cold engine(room temp)Resistance will increase if engine is warm
___________________________________________________________________________________________________
Ignition coil
disconnect wire(s) from coil terminal(s)
remove the spark plug leads from coil tower
test leads to
between (+) & (-) coil terminals
resistance (ohms) .02-.04
between coil tower & (-) coil terminal terminal 800-1100
Remember that just because they test good doesn't mean they are.(I know sort of messed up but that's the way this electronics stuff is.
If you where closer I'd let you test with the extra components that I have.
Good luck
I am thinking this is getting a little beyond me. I don't have any manuals for this motor, I did buy the online repair manual, which is great for specifics, but doesn't show you the over all of the motor, so you can even locate whre to start looking for some of these parts. I just hate to take it to a shop. I will give it a look over later today and see if I can even tell where these parts are. Thanks for all help.
Check your PM's
This should help you with finding the parts
https://www.mercruiserparts.com/Show_Pictures3.asp?dnbr=803127&ivar=images/COMMON/2563.png&inbr=3236&bnbr=40&bdesc=Ignition%2FElectrical+Components
This should help you with finding the parts
https://www.mercruiserparts.com/Show_Pictures3.asp?dnbr=803127&ivar=images/COMMON/2563.png&inbr=3236&bnbr=40&bdesc=Ignition%2FElectrical+Components
