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mariner 60hp problem

R

rodey

Contributing Member
need some help with my outboard,
its a 2004 3cyl 60hp 2stroke mariner,
seems to run fine a high speed but as soon as i drop revs to idle engine starts misfire and dyes . will not idle,
when it does ible it misfires and runs rough
its been with a guy over here now for 7 weeks and he cant understand it,
heres a few things that have been tried,
carbs clean, [dont thing its fuel related]
commpresion 120 on all cylinders,
checkd timing,
trigger coil changed,
stator coil changed,
flywheel [as one of the magnets were broke,
2 cdms,
tried the usual things like disconecting kill switch.
seems tu be breaking down on cylinder 2,
is there anything else that could be causing this,l
any help would be great.
 
Last edited:
It sounds like an intake leak - sucking extra air.

Carb gaskets, intake gasket (between manifold plate and reed block) would be my first two suspects. Extra "air" on intake, after the carbs, often manifests exactly as you describe your motor running - like crap at idle, often stalling unless you give it some throttle, but appears to run ok at higher rpms.

If those are fine, move on to the reeds themself (inspect for cracks, chips, improper closure/seal) and the crank seals. An issue with the upper seal is often apparent by a slick of oil under the flywheel. The lower one is somewhat more difficult to detect.
 
galamb said:
It sounds like an intake leak - sucking extra air.

Carb gaskets, intake gasket (between manifold plate and reed block) would be my first two suspects. Extra "air" on intake, after the carbs, often manifests exactly as you describe your motor running - like crap at idle, often stalling unless you give it some throttle, but appears to run ok at higher rpms.

If those are fine, move on to the reeds themself (inspect for cracks, chips, improper closure/seal) and the crank seals. An issue with the upper seal is often apparent by a slick of oil under the flywheel. The lower one is somewhat more difficult to detect.
Click to expand...

thanks for the reply.
i mention this to him but as far as hes concerned its not a fuel issue and has checked the reeds ,
its defo loosing spark on the 2nd cylinder
 
And it's only losing spark at number two at lower rpms? or it's only apparent at lower rpms?

If he is certain it's ignition related then I would look at the harness for the cdm coils and the confirm good ground between the cdm coils and the block - particularly on the number 2 coil.
 
galamb said:
And it's only losing spark at number two at lower rpms? or it's only apparent at lower rpms?

If he is certain it's ignition related then I would look at the harness for the cdm coils and the confirm good ground between the cdm coils and the block - particularly on the number 2 coil.
Click to expand...
.
ya he seem certain its electric

yes if i run it here in the yard it will run fine for say 10 mins or so then it goes down on one cylinder and only runs on 2 of them,
with a spark tester conected you can see no.2 spark going weak,
. thanks
 
If it's ok for maybe 10 minutes and then starts to lose spark (or spark gets quite weak), that may indicate that you have a cracked bobbin somewhere that has good continuity when it's "cold", but as it heats up and the copper expands, it starts losing continuity resulting in a loss of power with that individual component.

Again, I still wouldn't rule out the harness (kink or nip in the wire going to number 2 coil that may not be readily apparent).

You appear to have corrected the other options - stator and trigger - and unless you got a bad trigger (happens) I would re-focus on the harness at the moment.

You can disconnect the harness from both the trigger/stator connectors and from the number 2 coil. Use an ohm meter to check for continuity (find the relevant connectors that give you minimal resistance) - then take a hair dryer or heat gun and heat up the harness - watch for increasing resistance/loss of continuity.

That would be my next check.

If that all looks fine, then I would re-focus on both the trigger and stator. Same trick with the hair dryer...
 
galamb said:
If it's ok for maybe 10 minutes and then starts to lose spark (or spark gets quite weak), that may indicate that you have a cracked bobbin somewhere that has good continuity when it's "cold", but as it heats up and the copper expands, it starts losing continuity resulting in a loss of power with that individual component.

Again, I still wouldn't rule out the harness (kink or nip in the wire going to number 2 coil that may not be readily apparent).

You appear to have corrected the other options - stator and trigger - and unless you got a bad trigger (happens) I would re-focus on the harness at the moment.

You can disconnect the harness from both the trigger/stator connectors and from the number 2 coil. Use an ohm meter to check for continuity (find the relevant connectors that give you minimal resistance) - then take a hair dryer or heat gun and heat up the harness - watch for increasing resistance/loss of continuity.

That would be my next check.

If that all looks fine, then I would re-focus on both the trigger and stator. Same trick with the hair dryer...
Click to expand...

thanks mate give me abit more info on what to check out.
the hair dryer seems a good trick.
ill let you know how things go.
thanks
 
finnaly an end to this one,
changed all 3 cdms and away it went no more misfire,
just goes to show even if the ohms tests are ok doesnt mean the coils are still good.
thanks for all the help,
 
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