225txrr model won't start in cold temperature.

[Mervin225hp]

Hello,
I really hope I can find help here. I have a 225txrr 2 stroke model outboard engine year 1993 that won't start on mornings when the ambient temperature is below normal and the engine overnights. On mornings the engine turns over but does not pick up and continue idling. Sometimes I try starting with the throttle engaged, the engine starts and revs off but when i pull the throttle back to the neutral position it cuts off. After a couple failed attempts to start, if I let the engine sit for about 30 mins with the cover off and sun hitting the engine block, it will eventually start. Once started it works perfect the entire day till it overnights for next morning. If I go out at nights, I have to start the engine atleast every 2-3 hours interval for it to remain warm and ensure I start in the morning. If my first attempt to start is between 9am to 10pm while the environment is already warmed up with the sun out, it will start on one crank and works perfect. In my line of troubleshooting I have tried changing my primer bulb, separate gas container with proper venting, changed diaphragm on electric prime start and fuel pumps, tried different stator, tried different crank sensor next to flywheel, tried new 10 pin extension harness and new ignition, changed thermo switches on head, thermo sensor, cleaned engine harness, serviced carbs. I didnt try changing the pulser coil and engine ecu because I cant put my hands on any to try.
Can anyone advise on this issue or whether they came across it before? This engine has the micro ignition ecu mounted between the cylinder heads.
Regards,
Mervin

[99yam40]

My guess is the prime start is not giving enough fuel when real cold, if there is spark.

you say it will fire up when cold but will not idle, so there has to be spark all of the time.
does this prime start system have a red lever with a open position you can try?

but it would not be a bad idea to make sure all plugs are getting spark when this no start happens.

maybe there is a connection being affected by shrinkage because of cold

and how cold does it have to be for this to happen?

[Mervin225hp]

Hello Sir,

I am in Trinidad so the regular temperature range during the day from about 8am is like 31°-35°c throughout. At nights the temperature drops to approximately 24°c.

Yes, this engine has the prime start with the red lever. I've tried that and it will inject extra fuel into the carbs. If I leave the red lever open it will eventually flood the carbs.

I can't get my hands on another prime start to replace and see if thats the problem either. Is there a way to test that it is functioning properly?

On cold it will turn over, fire off a couple times like "duh duh duh duh" but shuts off. It doesn't pick up to continue idling. I can repeat this for half hour straight and it will not start up until either warmed up or not sure if anything is accumulating condensation so it waits till it dries off.

I've checked the sparks already and only one was weak. I changed that coilpack and plug but it didn't solve the issue. I could possibly retry this test.

When you mentioned shrinkage, what connection points are you referring to?

Our local yamaha dealer checked the serial number of this engine and saw it was from the UK which is colder than my region so I'm assuming the temperature sensors shouldn't send the ecu in any fail safe mode.

Thanks for the response.
Mervin

[99yam40]

I was thinking maybe you called cold below zero, I do not think connections will be a problem at those temps.

have you tried turning the red lever to open and as soon as it starts turn it back to normal or closed?

there are passages that extra fuel has to flow thru while cold.
I am not familiar with the prime start system on a 225, but I am sure a service manual for your motor would give test procedures

on My C40 you pull the heater unit out, measure the needle when cold, and then put 12v to the heater unit for a few minutes and remeasure to see if and how far the needle extends

even if the needle moves as it should the passage for fuel could be plugged

[Mervin225hp]

I have tried the red lever on the prime start. No difference on mornings but the carbs will eventually flood when I keep tumbling. During the day if I try the red lever and leave it open, it floods the carbs till it shuts off so I think the prime start is still very functional but not sure of the ratio in which it is.

When I said that I sometimes tried starting with the throttle engaged, the engine will start, revv and if I switched open the the red lever, you would hear the engine drowning with fuel until I pull the throttle back to neutral position and it will shut off.

Do you know where can I get a manual for this engine?

If I solve this issue I think I can help a lot of people here as many mechanics have come across this issue on this model without resolution.

[99yam40]

the red lever is there to just get it to fire off, need to turn to off or normal not suppose to leave it in the open position.
may need to open the fast idle lever a little to give it some air also when switched to open

I have no idea where to get a service manual for a UK motor

what is your procedure for starting the motor?
Prime bulb till tight, hit key for a few seconds, wait a little bit and hit key for a few more seconds, repeat as needed.
should start in 2 to 4 tries

[Mervin225hp]

I only left the prime start red lever on open just a couple times to monitor. Rarely uses it to fire.

Start up is normally:
1.Prime bulb till tight
2.Turn key to 1st position, wait for couple seconds
3.Turn key to 2nd position, engine tumbles for a few seconds.
4.Repeat step 2 & 3 for maybe 2 or 3 times. If no start...
5.I push the key in to engage the prime start, turn the key to 1st position for a couple of seconds.
6.Turn key to 2nd position and tumble engine for like 2 seconds and it normally either starts immediately with prime start or the second time with prime start.

Sometimes on my initial start during the day I just prime the bulb and skip straight to step 5 and 6 to use prime start and it usually starts up on 1st or 2nd attempt with no issue.

With reference to step 2 & 3 above, the engine mostly tumbles freely without firing. Once I hit prime start, it fires immediately.

On the cold mornings, if I use the prime start, it fires off and turns the engine for a second but doesn't pick up and idle. It just turns over, the exhaust goes "duh duh duh duh" like it's about to start like normal but shuts off.

A couple of times when I get it to turnover on the cold morning and catches it with the throttle, I accelerate the throttle, the engines revs off, I hold the throttle at maybe quarter position for about 30 secs, the engine works for this 30 secs but once i ease off the throttle to neutral, it shuts off and I get the same starting issue right after.

About 2 times, the engine started on land normal on the cold morning, I ran the engine for like 2 or 3 minutes but then when I launched the boat in the water, I get the same issue till the sun comes up and we wait till maybe 830am before it starts normal.

could it be the plug wires or coil packs accumulating condensation and when it dries off then it works?

Will the ecu cause this on this model?

[99yam40]

as far as I know pushing in the key is just for a motor with a choke, it does nothing for a prime start motor.

I know nothings about the ECU con*****ing any of the prime start

[Mervin225hp]

When I push the key in and turn to position 1 on the ignition, you will hear the solenoids on the prime start click. Not sure if it opens any jets or engages it to pump but that is how the prime start is set up to work on this engine model.

Thanks for your information thus far. I will do some more troubleshooting based on your recommendations and provide feedback.

[99yam40]

apparently this prime start system is way different than the ones on the small 3 cylinder motors that I have dealt with.
so someone else will have to chime in to help you

[TownsendsFJR1300]

Are you sure you have Prime Start and not a simple choke solenoid with choke butterfly(s)?
Your description of how it's working (pushing in the key), sounds like a solenoid / butterfly...

I don't see either in the parts diagram: https://www.boats.net/catalog/yamaha/outboard-by-year/1993/225txrr/carburetor

Crappy pic but that's what's available here..

Capture.JPG

[99yam40]

he did say he has the red lever for the prime start.
I am hoping that is not a manual choke

and being a UK model, who knows what could be different from those around here

[panasonic]

There is a Prime Start on that engine..no choke. Not like any Prime Start I have seen. It has what appears to be two solenoids on it maybe? Item #46.

[panasonic]

Mr Mervin is this the prime start on your engine?

[99yam40]

does anyone think those solenoids would inject extra fuel when you push the key in?
My old 35 Evinrude had something like that .
if the electric did not function ,it had a manual lever you could move back and forth to squirt fuel into the carb .

I really do not think Yamaha ever had anything like that they called prime Start

Maybe Boscoe can enlighten us