tengals123
Master Chief Petty Officer
- Joined
- Jan 26, 2005
- Messages
- 860
Ok, I have not been around for a while, but boating and fishing like crazy over the past coupla years,
Whenever I have a problem with my mercs i always come here to read-up and work it out
I am a MERC man, with firstly a 100hp 1968 Tower of power, to a 1998 2+2 115hp merc, to currently a 1988 2+2 100HP merc.
now I would like to provide some free info as reference to all for later use it's my "giveback"
ok most will know the 2+2 from 88 era to 98 and somewhat beyong have not really changed anything, basically very similar motors, same carbs, etc....
ok, now,
my 1988 merc 6 months ago mid snapper season starteed to idle shocking. popping, shotgunning out the exhaust running like a paintmixer on my transom.
then occassionally if would idle fine for 30mins or so, then slip back into dogsballs state.
it was exremely frustrating,
so heaps of checks were done, by oneself.....
comps were fine,
carbs were pulled, floats checked, kits installed 9full kits) cleaned, re-assembled and installed, reeds were checked, link and sink was done, timing was done, fuel was changed, oil was upgraded to premium.......still ran at idle like crap, made no difference......
them, of course "electrical" has to be the problem, we all have the word "electrical" on merc, as we know the huge $$$ we're in for,
so the test were done on the trigger, stator, coils, switchbox, gap test etc....
all came out great, great jump, great voltages (DVA), stator test was good, only low speed was right on High spec, but just in.....
so, still running like crap.....shotgunning, popping, shaking, etc all the commin symptoms of a rough idling 2+2 merc....
them it occured..............
when pulling the plugs running at idle, I only ever pulled plugs 1 and 2, becuase below 1800 these motors only run on 1 and 2 cyls., so no need to pull 3 and 4 becuase over 1800-2000rpm this baby purred.....
so, I thought as a last resort, i'd pull 3 and 4 boots while the motor was idling, and what! the rpm changed.......
then WHAT!, with 3 and 4 disconnected, it idleed perfect!
so, spark continues to 3 and 4 on these motors upto 1800rpm, but NO fuel is provided to 3 and 4 till 1800rpm....
so then the boots were connected back upto 3 and 4 but clamped the fuelline going to the fuel accelrator pump...
what do you know...............
with all 4 plugs sparking but no fuel to the accelerator pump, the motor sounded like it was brand new straight out of the showroonm idling perfectly at 700rpm
ok, so the accelerator pump was dis-mantled and the diaphram looked ok the little brass disc, spring etc was ok........ had me stumped again..........
so I followed the line past the accelerator pump to the CHECK VALVES!!!!!!!!!! that head into 3 and 4
apon removal, I noticed some crud in these areas,
once removed, cleaned and re-seated and then re-installed, the motor still ran idled shocking,
about to give up,,,,,
curiosity got the better of me and pulled them again 9the check valved to 3 and 4, checked the seating again and fixed the 2 brass peices together, but this time didnt screw them into the block.......
I pumped/primed the fuel bulb, and...........
what do you know?????????????????
fuel starts poring out of the check valves.............
THEY ARE NOT SEATING PROPERLY, expecially number 4.........
so apon replacing new, springs and needles in 3 and 4 check valves,
fire her up and
BANG! spot on sitting perfect at 750rpm......
just like out of the showroom
now i only wanted to sher this as a "give-back"
to the 100's of posts and threads on
check your stator, carbs, pull the carbs again, check the floats again, change your fuel again, check your switch box etc....
all the posts seem similar......
so this one is a bit different,
Point to the story,
if your 2+2 motor is idiling like crap, and you have tried everything,
then PLEASE CHEACK you accelerator pump and check valves, easy to check...
becuase even if a "little" bit of fuel is getting into 3 and 4 below 1800rpm, it will make the motor run shoking at idle........
I really hope this post helps some-one oneday
as iboats helped me so many time
best wishes all...
cheers
Whenever I have a problem with my mercs i always come here to read-up and work it out
I am a MERC man, with firstly a 100hp 1968 Tower of power, to a 1998 2+2 115hp merc, to currently a 1988 2+2 100HP merc.
now I would like to provide some free info as reference to all for later use it's my "giveback"
ok most will know the 2+2 from 88 era to 98 and somewhat beyong have not really changed anything, basically very similar motors, same carbs, etc....
ok, now,
my 1988 merc 6 months ago mid snapper season starteed to idle shocking. popping, shotgunning out the exhaust running like a paintmixer on my transom.
then occassionally if would idle fine for 30mins or so, then slip back into dogsballs state.
it was exremely frustrating,
so heaps of checks were done, by oneself.....
comps were fine,
carbs were pulled, floats checked, kits installed 9full kits) cleaned, re-assembled and installed, reeds were checked, link and sink was done, timing was done, fuel was changed, oil was upgraded to premium.......still ran at idle like crap, made no difference......
them, of course "electrical" has to be the problem, we all have the word "electrical" on merc, as we know the huge $$$ we're in for,
so the test were done on the trigger, stator, coils, switchbox, gap test etc....
all came out great, great jump, great voltages (DVA), stator test was good, only low speed was right on High spec, but just in.....
so, still running like crap.....shotgunning, popping, shaking, etc all the commin symptoms of a rough idling 2+2 merc....
them it occured..............
when pulling the plugs running at idle, I only ever pulled plugs 1 and 2, becuase below 1800 these motors only run on 1 and 2 cyls., so no need to pull 3 and 4 becuase over 1800-2000rpm this baby purred.....
so, I thought as a last resort, i'd pull 3 and 4 boots while the motor was idling, and what! the rpm changed.......
then WHAT!, with 3 and 4 disconnected, it idleed perfect!
so, spark continues to 3 and 4 on these motors upto 1800rpm, but NO fuel is provided to 3 and 4 till 1800rpm....
so then the boots were connected back upto 3 and 4 but clamped the fuelline going to the fuel accelrator pump...
what do you know...............
with all 4 plugs sparking but no fuel to the accelerator pump, the motor sounded like it was brand new straight out of the showroonm idling perfectly at 700rpm
ok, so the accelerator pump was dis-mantled and the diaphram looked ok the little brass disc, spring etc was ok........ had me stumped again..........
so I followed the line past the accelerator pump to the CHECK VALVES!!!!!!!!!! that head into 3 and 4
apon removal, I noticed some crud in these areas,
once removed, cleaned and re-seated and then re-installed, the motor still ran idled shocking,
about to give up,,,,,
curiosity got the better of me and pulled them again 9the check valved to 3 and 4, checked the seating again and fixed the 2 brass peices together, but this time didnt screw them into the block.......
I pumped/primed the fuel bulb, and...........
what do you know?????????????????
fuel starts poring out of the check valves.............
THEY ARE NOT SEATING PROPERLY, expecially number 4.........
so apon replacing new, springs and needles in 3 and 4 check valves,
fire her up and
BANG! spot on sitting perfect at 750rpm......
just like out of the showroom
now i only wanted to sher this as a "give-back"
to the 100's of posts and threads on
check your stator, carbs, pull the carbs again, check the floats again, change your fuel again, check your switch box etc....
all the posts seem similar......
so this one is a bit different,
Point to the story,
if your 2+2 motor is idiling like crap, and you have tried everything,
then PLEASE CHEACK you accelerator pump and check valves, easy to check...
becuase even if a "little" bit of fuel is getting into 3 and 4 below 1800rpm, it will make the motor run shoking at idle........
I really hope this post helps some-one oneday
as iboats helped me so many time
best wishes all...
cheers