2.5 timing settings off from other motors

**johnmiffco** · 08-01-2016, 12:06 PM

have a WTF is going on ?
have triple 2.5 260+ motors on my boat
from time I built the motors my center motor timing arm
has to go almost to where the arm stops hitting the top cap bolt
to get my 25 deg full timing,,,,max arm travel maybe hit 26
the other 2 timing arms in basic same location or common area
im used to seeing for last 20+ yrs
motor runs fine.......
couple weeks ago I lost a switchbox on this motor
so bought new rapair trigger and 2 switchboxes to put all new
when went to time arm hit its end at 22deg,,,,huhh
so rechecked tdc with dial indicator and 150 for 25 deg timing on flywheel
so swapped flywheel from other motor,,,same 22deg,,,,
put on another stator,,,knowing stator just makes voltage,,,but still tried,,,same 22
put on another merc trigger,,,not the same original,,,went back to 25 with arm running out of travel
,,,,,,again is running fine and plugs are reading like other 2 motors,,power seems the same
so ? is
could this crank be twisted some? if so then maybe 2-6 timing is off a tad if #1 times out
or when merc made crank they had the splines off just a bit,,,,,
makes u go WTF
john

**David - WI** · 08-01-2016, 12:27 PM

If it indicates out as you say; doesn't it almost have to be the little link at the top of the timing arm that connects to the trigger?

**johnmiffco** · 08-01-2016, 12:39 PM

thought of that when 1st put it together,,,,,over a yr ago and approx. 125 hrs and still runnin good
link is screwed all the way in making it as short as possible an I even flipped it as the 90deg elbow is longer on 1 end
as stated the other 2 motors time out where I have seen them for yrs,,,,,,about the same length on the stopper screw on the arm
ive been timing v6 mercs since 1981,,,,,,so kinda got degreeing down,,,
this crank can screw stopper till does not touch block and trigger arm hits top cap
and with the new trigger wouldn't make 25
used merc trigger does but barely
plugs and piston tops have same look as other motors
as why gotta be crank off
just never seen it before and seeing if any1 else seen it

**David - WI** · 08-01-2016, 12:55 PM

Doesn't the link have to be longer if you want more advance?

**johnmiffco** · 08-01-2016, 12:59 PM

trigger arm is behind throttle arm
so shortening the link pulls trigger arm closer to throttle arm
again trigger arm is running out of travel to get to mark
as is crank spline are in wrong location,,,thus starting timing retarded causing having to move trigger further
to get to idle and full timing locations

**WillySteve** · 08-01-2016, 03:17 PM

It could be twisted a bit John but if the merc trigger gets you to 25 then I'd run with it if there's no additional vibration.
Running N2o on my old motas, I've broke driveshaft's at the upper splines and twisted splines on several propshafts but never seen a crank twist but it's dang sure possible!
JMO

**johnmiffco** · 08-01-2016, 03:31 PM

yes it times out just the trigger goes 1/4" window further than any other ive ever adjusted
and been runnin them hard over a yr
cruise 5-6k all day long
and take to 7500+ when water conditions are good
when the 1 switchbox failed got me thinking about it again,,,,,lol
I run over 100gallons through motors every time out and past over 100 hr in last yr
flywheel hub/trigger gives the signal so gotta be a spline off from factory
as spline is all straight and flywheels slide on smoothly with no burring on splines
or its a bit twisted,,,,,,,
just asking if any1 else seen it
as in 30+ yrs and a few hundred builds never seem it,,,,,,

**David Borg** · 08-01-2016, 04:23 PM

I would try to swap the flywheel,unless you already did

**WillySteve** · 08-01-2016, 04:25 PM

It's alot'a work but you could switch stator, trigger and flywheel from another engine and see if the problem moves. If it don't it has to be either the crank or the upper bearing carrier!

**johnmiffco** · 08-01-2016, 04:58 PM

already stated on 1st post
have used 2 different stators,,,3 different triggers,,and did swap flywheels
as stated rechecked with indicator tdc and 25 to the timing marks on wheel to pointer
the flywheel change did not change timing on other motor
the new rapair was off from a merc,,,
and 2 mercs hit timing mark
just only factor staying same is the crank spline,,,,,
so spline in my mind has to have been cut off some,,
or crank has a twist
don't see how a bearing carrier can change timing
crank is not shaking,,,,flywheel is steady when running
but all 3 motors have the same upper cap
and timing arms
have to use all of triggers travel to get 25
and timing arm stop to block is way shorter for the more travel to get timing to hit mark
motor runs fine,,,,been that way for many hrs of run time
forgot about it till I lost a switchbox
and wanted all new electronics
as its an offshore boat and go 100+ miles in a day all the time

**David Borg** · 08-01-2016, 05:02 PM

With all the above mentioned the crank splines must be off. I doubt the crank is twisted though

**WillySteve** · 08-01-2016, 05:19 PM

The only reason I mentioned the Bearing Carrier is because the window in the casting could limit the travel of the trigger were it off a little!
JMO

**johnmiffco** · 08-01-2016, 05:24 PM

my thoughts also,,,,,
as never seen before timing arm to go approx. .0320 more than another to get 25
measuring the length of the stop screw on the throttle arm
and really is more as I adjusted the trigger swivel as short as possible to advance timing more to arm location
just never seen this and wondering if any1 else ever had 1
I guess it was a Monday crank and their alignment indicator was off on the spline cut
is only thing making sence
u guarantee another crank is going in when I refresh motors
just for peace of mind reasons,,,,lol

**johnmiffco** · 08-01-2016, 06:13 PM

Originally Posted by WillySteve

The only reason I mentioned the Bearing Carrier is because the window in the casting could limit the travel of the trigger were it off a little!
JMO

yea I figured so as why said they were all same top bearing caps
all 3 are 260 unpainted caps

**David - WI** · 08-01-2016, 07:18 PM

But one spline off would be over an inch out at the rim of the flywheel; I just can't believe that would get by even a casual inspection. I guess anything is possible but it seems like there has to be something else going on.

When you indicated it out, your "0" would have been off by about 1-1/8" I think.

Edit: never mind... it could be off by any amount; not necessarily 1 spline.