Force 125 lacking power

[125]

Thanks for answer hoping to get a look weekend

 

[jerryjerry05]

Just leave the others hooked up to the plugs.
Undo the one your working on and check for spark.

 

[Redbarron%%]

While not a definitive check clamping an induction timing light on each plug wire will show you that there is a discharge current on each wire, but not necessarily a nice fat spark.
It is quick and dirty, but will quickly indicate something like a bad trigger coil or dead ignition coil.

 

[125]

Ok thanks all will report when had a look blooming cold here now to look at boat never mind get it out on water

 

[jerryjerry05]

I keep an old lawn mower spark plug in
my tool box when I do a spark check.

 

[125]

Hi everyone finally got a look at boat spark tester etc found some bad wires on harness that when moved about caused erratic spark misfire repaired started all sounded good revved In tank first couple of times sounded like the old girl was back to life but after a small amount of idling it got boggy and once again the smoke was thick oil residue in tank then revving was not clean I thought maybe it was residual but seemingly running for quite a while gets no better and only way to get to run happily is to have mixture screwed in far to weak so I am back to drawing board again I think eagerly waiting for next ideas sorry for long message

 

[jerryjerry05]

If the air screws need to be almost all the way in??
You probably have an air leak somewhere?
Do the starting fluid test and see if you can find it?

 

[125]

Hi all been an age since got a look at boat got a few hours in today so I’m now at point of really lost recirc covers new pump diaphragm another set of plugs just in case got fouled messing around two cdi units one new coil new fuel and filter timing checked carbs stripped cleaned spark tested jumps huge on all 4 cylinders now starter fluid test compression test even all 4 150. Can I do a cylinder leak test on a two stroke I’m now wondering if it is maybe cross firing between head gasket. Is it possible to have an exhaust blockage or any of you wise and experienced guys have any more ideas for me the uk is very lacking in marine engineers and to find one who will look at force is proving close to impossible don’t know whether my last ideas are clutching at straws but would have hoped to be there by now thanks all and happy new year everyone

 

[Nordin]

I have read through the whole thread and sometimes it is hard to understand what you have done cause every posts are a whole long sentence.
Please use . and , in your post, much easier to read.

Well back to your issue. You seams to have done most of the checking but have you looked at the reed valves?
They are just behind the carbs in the intake manifold.
Steel pedals in V blocks.

 

[125]

I have read through the whole thread and sometimes it is hard to understand what you have done cause every posts are a whole long sentence.
Please use . and , in your post, much easier to read.

Well back to your issue. You seams to have done most of the checking but have you looked at the reed valves?
They are just behind the carbs in the intake manifold.
Steel pedals in V blocks.

I have only looked through at them when carbs were off didn’t do anymore as I was told any problem with reed petals would cause hard starting and popping banging and such like which I have none of.if you didn’t know the boat it’s useable and just very lacking in power and does not reach max rpm no pullout power and the only other noticeable when run in tank is extreme 2stroke smoke but that is not noticeable out on the water.thanks for taking time to read and interpret my grammar etc any ideas from anyone are very welcome.

 

[jerryjerry05]

Reeds: If the reeds are bad they will let gas come back through
out the front of the carb.
When you pump the ball to prime the motor, does the ball get hard?
I know you changed the diaphragm but it could have gone bad??

 

[racerone]

With the lack of power there is a issue with 1 of 5 things.-----Wrong timing or no spark on one cylinder.-----Not enough fuel / too much fuel going in to one or more cylinders.---Lack of compression in one or more cylinders.-----Lack of crankcase compression in one or more cylinders.-----Blockage in exhaust housing.------Some orderly trouble shooting will find the issue.

 

[125]

Reeds: If the reeds are bad they will let gas come back through
out the front of the carb.
When you pump the ball to prime the motor, does the ball get hard?
I know you changed the diaphragm but it could have gone bad??

Hi Jerry I have spoken with you on this 125 before and carried quite a few repairs and tips you gave me each of which I have found some thing wrong but still not the cure for as long as I’ve had this engine fuel has come from front of carbs when tilted up. I changed the diaphragm when I done cross fire covers as thought that was lost power cause I’m still not running right could it be an exhaust blockage like has been suggested how do I look for that I really am at the end now but have no suggestion or recommended persons in uk to look at it so for now have to continue myself many thanks to every one reading and suggesting and throwing ideas for me

 

[125]

With the lack of power there is a issue with 1 of 5 things.-----Wrong timing or no spark on one cylinder.-----Not enough fuel / too much fuel going in to one or more cylinders.---Lack of compression in one or more cylinders.-----Lack of crankcase compression in one or more cylinders.-----Blockage in exhaust housing.------Some orderly trouble shooting will find the issue.

Thanks for reply and your time I have been going through for quite a while now started with renewing crossfire recirc system fuel pump diaphragm new fuel new separator new in line filter carbs stripped and cleaned link and sync timing spark jump test resulting in two cdi units new coil all new connectors on wiring.starting fluid test around intake compression test all up 150 ish the reason I asked can I do a cylinder leak off on a two stroke is that have had a few 4stroke cars that cross fire between cylinders dependant on where head gasket blows I also asked on forum about exhaust blockage but you are first to suggest can you tell me how to investigate that. I have owned this engine from brand new some people have listened and say it sounds fine but I know it very well and it is labouring in tank and the only other clue I can give is that it is emitting about ten times the usual amount of smoke and turn tank water into an oily mess in no time at all.i feel when doing cylinder drop test that no 2 is making very little difference most of time when you remove it the other cylinders when removed cut the engine which suggests to me that no2 is not firing strong enough when other leads removed is not enough to maintain running on three cylinders everything that has been done I have found something wrong with and thought when turning key was going to be cured.have 4 huge blue sparks timing spot on good fuel and delivery good compression but the old girl still not running any good any suggestions gratefully received thank dave

 

[jerryjerry05]

Snake camera, depending on your camera(I have Android)in the US they can be gotten for 12$ Look on ebay and get the one with the stiff lead.

Blockage in the exhaust: test: Remove the lower unit, get a snake camera
and look up inside the exhaust. I'd be REALLLLY surprised if that was the problem?????
The fuel from the carbs when tilted, that will happen as long as the carbs have fuel in them when the motors shut down.
You rebuild the carbs? then the float might be set wrong? or there's something blocking the main jet?
Are all the plugs burning the same? #3 from the top, is it the same as the others?
Remember the quick start test? try again.
I had a blown head gasket and still had 145# on all cyl.
Remove the inline hose connectors(sucking air).
Fuel tank: built in the hull or carry-on? Check the vents on both,
the built in can have bugs in the line blocking it off.
The carry-on: the vent usually has an o-ring and it can move and block off
the air??
Lastly: overheating? Test the alarm, ground the orange lead at the buss bar.
That should make the alarm sound off.
Again ebay for another tool: heat gun $16 US
Get it running and check the heat on the head side of the motor.
Keep us posted.

 

[125]

Snake camera, depending on your camera(I have Android)in the US they can be gotten for 12$ Look on ebay and get the one with the stiff lead.

Blockage in the exhaust: test: Remove the lower unit, get a snake camera
and look up inside the exhaust. I'd be REALLLLY surprised if that was the problem?????
The fuel from the carbs when tilted, that will happen as long as the carbs have fuel in them when the motors shut down.
You rebuild the carbs? then the float might be set wrong? or there's something blocking the main jet?
Are all the plugs burning the same? #3 from the top, is it the same as the others?
Remember the quick start test? try again.
I had a blown head gasket and still had 145# on all cyl.
Remove the inline hose connectors(sucking air).
Fuel tank: built in the hull or carry-on? Check the vents on both,
the built in can have bugs in the line blocking it off.
The carry-on: the vent usually has an o-ring and it can move and block off
the air??
Lastly: overheating? Test the alarm, ground the orange lead at the buss bar.
That should make the alarm sound off.
Again ebay for another tool: heat gun $16 US
Get it running and check the heat on the head side of the motor.
Keep us posted.

Sorry Jerry don’t remember what the quick start test was or are you talking about starting fluid test. Sorry if repeating but the reason I said about head gasket was that with good spark good fuel I cannot think of anything else that would make cylinder number 2 fire weak ie when 1 3or 4 lead is pulled while running engine cuts out no 2 pulled engine runs and putting lead on and off no 2 makes very little difference which is leading me to think no2 is not firing as strong as the other cylinders.i have a bore scope that I can use to check exhaust but I as you cannot see this being problem as seems to be effecting only one cylinder.some one on forum said about exhaust and anyone that takes time to read and post suggestions has my ear thanks Jerry and to all that are putting stuff on re my problem thanks all Dave

 

[125]

Sorry Jerry don’t remember what the quick start test was or are you talking about starting fluid test. Sorry if repeating but the reason I said about head gasket was that with good spark good fuel I cannot think of anything else that would make cylinder number 2 fire weak ie when 1 3or 4 lead is pulled while running engine cuts out no 2 pulled engine runs and putting lead on and off no 2 makes very little difference which is leading me to think no2 is not firing as strong as the other cylinders.i have a bore scope that I can use to check exhaust but I as you cannot see this being problem as seems to be effecting only one cylinder.some one on forum said about exhaust and anyone that takes time to read and post suggestions has my ear thanks Jerry and to all that are putting stuff on re my problem thanks all Dave

Ps was going to put pipe straight from a Jerry can to pump just as matter of course but again done think it’s that as seems to be only no2 also overheat buzzer works temp all good buzzer tested to ground now and have always tested frequent also this problem hasn’t got progressively worse it went like a rocket on-trips out as normal then went out one day have about a 2 mile 8 mph trip through moorings and restrictions. Went to pull away and that’s when problem reared it’s head sorry for rambling but just trying to put as much info as poss

 

[125]

Ps was going to put pipe straight from a Jerry can to pump just as matter of course but again done think it’s that as seems to be only no2 also overheat buzzer works temp all good buzzer tested to ground now and have always tested frequent also this problem hasn’t got progressively worse it went like a rocket on-trips out as normal then went out one day have about a 2 mile 8 mph trip through moorings and restrictions. Went to pull away and that’s when problem reared it’s head sorry for rambling but just trying to put as much info as poss

 

[125]

One other just thought of I am counting cylinders from top to bottom top being counted no1

 

[jerryjerry05]

Starting fluid/quick start test.
Start motor and spray the SF around the intake side of
the motor.
Spray at the base of the carb and around the back to the
port covers on the stbd. side.
Then if that makes the motor run different, stutter,cough
stall? Then the motors sucking air.

Since it seems centered around #2 then I'd take a guess and
say maybe one of these things is happening??
The trigger leads to #2 are very tiny and thin, they loose
contact under the shrink wrap on the connector, try pulling
on the leads and see if it comes out. I replace ALL connectors
when I find one gone bad.
OR? the coil is breaking down under load, try swapping with
another coil. In 35+ years I've only seen 1 bad coil but it's possible.
Check the ground wires on the coils.
OR? the port cover under the packs and coils. The gasket has
blown. One tiny cough, backfire, or miss can blow the gasket.
OR? The reeds on that cyl. are bad?
Check these things and let us know??