'93 25hp 2 stroke Spark Plug Issue??

[Jason2tpa]

All great info thanks. And what about leaning up the mix? Whenever I've pulled plugs a wet oily residue remains.

[Jason2tpa]

Re: Smoking

I mean its a 2 stroke...it smokes, right? It doesnt smoke a lot tho no. Plus i keep seafoam in tank which also contributes to smoking.

Does it smoke a bunch when it finally starts?
If so, its a sign of flooding.

If your letting it idle for awhile during flushing it could be loading up slowly during that long idle, especially if its a bit rich... even at 100:1?? I dunno...
IF it is loading up, and its not cleared out before its shut off it could make it hard to start next time around.
(We have one particular SeaDoo with twin carbs that'll get very pissy on its next start if its not blown out on the hoist after the long no-wake idle down to our dock. Big blast of blue smoke every time, been that way since new ~2001)

Disconnect your fuel line while flushing/idling... that should empty it out, carb and cylinders both.
When its time to start again, pump your bulb till it firms and hold a wee little bit of pressure on it for a couple of seconds, you may feel it collapse some as the float bowl fills up again, if so squeeze it gently once more to firm back up.

The plugs could be fouling because of flooding combined with a too small gap.

When cold, it should be started with the choke fully closed and as much throttle as it will allow in neutral.
IF it fires, but does not start, THEN open the choke for a few pulls, if it doesn't fire again then close the choke once more to draw in more fuel.
The objective is to get enough fuel in there to start, but not so much it floods. Sometimes, being quick to open or half-position the choke when they sputter to life will save you a few more pulls.

I have never come across a 2-stroke that will cold start without choking, even after sitting for just 10-20 minutes most needed that additional sip to get going again easily.

[Dashunde]

And what about leaning up the mix? Whenever I've pulled plugs a wet oily residue remains.

I dunno really... It depends on when its becoming flooded?
I can only guess your idle mix setting is ok, otherwise it wouldn't idle very long while flushing, instead it would start to sputter, rattle around and finally die.

My guess is your getting it flooded while trying to start it?

You might also want to invest in a new clean tank, mail fuel line, and all inner lines.

Tread lightly with all of the spark plug pulling.
It doesn't take much to wear out those aluminum threads.
Finger tight then just snug with a wrench.

I'm still trying to figure a few things out...
How long have you had this engine?
Did it just start giving you starting problems recently?
More background on it and your experience with engines might help.

[Jason2tpa]

I bought the engine on craigslists 3 months ago. Sitting in a guys backyard needing a water pump. He didnt want to do it. Since then ive replaced the water pump, thermostat and gasket, plugs, cleaned carbs w new kit, along with fixing/replacing a few other small things.

Idle set is good. One thing i forgot to mention is only one of the choke flaps works. Actually there is only one choke flap. This part, along with a few other carb parts were missing. I was given a replacement flap w screws but is impossible to thread the screws in bc they once installed by manufacturer the distal end of threads flare.

Re: Flooding
Im confused. You suggested when I initially start engine to fully choke (meaning the flaps are closed?) and open throttle fully. How does these two together not flood the engine?

Great advice about the frequent plug pulling.

This is my first outboard engine, though Ive been around boats for 30+ years. Mechanially inclined and a insatiable appetite to know everything lol. As you can probably gather from my posts.

Ive been having either fuel or ignition problems since getting engine. I knew this was a fixer though. Just a matter of fine tuning everything. Learning its quirks.

I dunno really... It depends on when its becoming flooded?
I can only guess your idle mix setting is ok, otherwise it wouldn't idle very long while flushing, instead it would start to sputter, rattle around and finally die.

My guess is your getting it flooded while trying to start it?

You might also want to invest in a new clean tank, mail fuel line, and all inner lines.

Tread lightly with all of the spark plug pulling.
It doesn't take much to wear out those aluminum threads.
Finger tight then just snug with a wrench.

I'm still trying to figure a few things out...
How long have you had this engine?
Did it just start giving you starting problems recently?
More background on it and your experience with engines might help.

[Dashunde]

I bought the engine on craigslists 3 months ago. Sitting in a guys backyard needing a water pump. He didnt want to do it. Since then ive replaced the water pump, thermostat and gasket, plugs, cleaned carbs w new kit, along with fixing/replacing a few other small things.... Ive been having either fuel or ignition problems since getting engine. I knew this was a fixer though.....

This sounds all too familiar, myself and friends alike... repeatedly... and no, it may not turn out to be a "fixer"... instead it may reveal itself as a steaming time-n-money crap pie with a big scoop of frustration on the side.

Re: Flooding
Im confused. You suggested when I initially start engine to fully choke (meaning the flaps are closed?) and open throttle fully. How does these two together not flood the engine?

Right, closed choke = flap closed.
Since the engine can not easily draw in as much air as it wants it will draw more fuel from the bowl due to the excess vacuum.
Pulling many times with the choke closed will indeed flood it quickly.
The question would be why didnt it fire off earlier, when it should have? See further down regarding your missing flap.

The idea is that it should fire when the right amount of fuel has entered, one, two, three pulls... somewhere in that range, and start opening the choke right away to allow in the air it needs to keep going once it fires.

Dont open the throttle fully, just to the "start" position or its max throttle position allowed by the linkage when its in neutral.
Save the wide open throttle/closed choke starts for the weedeaters and such.

One thing i forgot to mention is only one of the choke flaps works. Actually there is only one choke flap. This part, along with a few other carb parts were missing. I was given a replacement flap w screws but is impossible to thread the screws in bc they once installed by manufacturer the distal end of threads flare.

First, I dont have intimate knowledge of the crankcase for your motor, but it looks like each carb solely feeds its own cylinder.

If thats the case you've got a fundamental starting problem... one cylinder gets enough fuel to fire, but it might not be its turn when you pull the cord, meanwhile the carb that is due to fire doesnt have enough fuel and it all gets messed up from there.
Sometimes you get lucky and the right amount of fuel aligns with a cylinder that is ready to go.

I really suggest you sort out the missing choke issue and move on with it from there.

[Dashunde]

Double post...

[Jason2tpa]

This is my first consistent use of a pull start outboard. I definitely have not gone about starting using your procedure. I had been closing choke completely, with 3/4 to full throttle in neutral to start. And continuing this throughout if i had problems...which by learning of the proper way you state IS the problem. Now I understand what's occurring in the chamber thanks. The only fix for the flap is a new carb, so im told by the yamaha mechanic. Im trying to get away without doing that.

This sounds all too familiar, myself and friends alike... repeatedly... and no, it may not turn out to be a "fixer"... instead it may reveal itself as a steaming time-n-money crap pie with a big scoop of frustration on the side.



Right, closed choke = flap closed.
Since the engine can not easily draw in as much air as it wants it will draw more fuel from the bowl due to the excess vacuum.
Pulling many times with the choke closed will indeed flood it quickly.
The question would be why didnt it fire off earlier, when it should have? See further down regarding your missing flap.

The idea is that it should fire when the right amount of fuel has entered, one, two, three pulls... somewhere in that range, and start opening the choke right away to allow in the air it needs to keep going once it fires.

Dont open the throttle fully, just to the "start" position or its max throttle position allowed by the linkage when its in neutral.
Save the wide open throttle/closed choke starts for the weedeaters and such.



First, I dont have intimate knowledge of the crankcase for your motor, but it looks like each carb solely feeds its own cylinder.

If thats the case you've got a fundamental starting problem... one cylinder gets enough fuel to fire, but it might not be its turn when you pull the cord, meanwhile the carb that is due to fire doesnt have enough fuel and it all gets messed up from there.
Sometimes you get lucky and the right amount of fuel aligns with a cylinder that is ready to go.

I really suggest you sort out the missing choke issue and move on with it from there.

[TownsendsFJR1300]

Generally, your throttle should be open just slightly when starting (maybe 1,000-1200 rpms). When you hold the throttle WOT when pulling, your clearing out excess fuel(working against your self).

Try the throttle there, full choke a pull or two, then less choke, it should fire up (the missing carb, choke plate is the wild card)..

You can likely find a used carb for the plate on Flea Bay for cheap..

[99yam40]

How do you expect a choke to work if parts are missing?

Look for a replacement carb with all the parts included.

Hope the parts that are missing did not go into the motor somehow

[Jason2tpa]

Ive replaced the missing parts. The one choke flap is the only part not installed.

How do you expect a choke to work if parts are missing?

Look for a replacement carb with all the parts included.

Hope the parts that are missing did not go into the motor somehow

[99yam40]

Without the choke flap/plate the choke will not work

[TownsendsFJR1300]

How do you expect a choke to work if parts are missing?

Obviously, all the parts there would be the best.

Being a two cylinder engine, as long as the one butterfly works properly,
the engine may fire up on one "good" cylinder, it'll run rough till warm, but run.

**Reading back thru the previous posts, the above does indeed work (as he has been running the engine). BUT, its a PIA trying to get everything exactly right for a correct cold start (till ALL the parts are properly installed)**.

[Jason2tpa]

I recon when its full choke it's really half choke cause only one flap. So at best only half choke is possible to start. If needed, I guess I could remove the vent cap and hold my hand over the carb with the missing valve. Though thats a pain in the ass. Let me try properly starting engine with the sequence you recommended. If it consistently starts on one then I dont have to replace the carb. Fingers crossed. Thanks for all your assistance.

Without the choke flap/plate the choke will not work

[zenoahphobic]

Choke

Has it been confirmed that this motor is indeed choked on every carb? Most only have one "choke flap"!
You might be barking up the wrong tree or I am.

[Jason2tpa]

Indeed it has been confirmed. Two flaps linked to operate together by one pull knob.

Has it been confirmed that this motor is indeed choked on every carb? Most only have one "choke flap"!
You might be barking up the wrong tree or I am.