70TLR Cold Start

[boham1978]

Hello all! I have been doing a ton of reading here on my 2006 outboard motor. When it is cold, I have to crank it over for a good minute while messing with the fast idle lever to get it to finally start. When it's finally started and warmed up, it starts like a dream every time. I used to think that I had a choke solenoid issue until reading these forums and finding out that it is a PrimeStart.

The previous owner told me that since he has had it, it always takes a good minute of cranking when cold before it will fire up. This just doesn't sound right to me.

Are there any checks to do to see if the PrimeStart is working properly? I pulled it off cold and the needle is sticking out about 1/2". When you crank the engine, power is being applied to it. The red lever is in the closed position.

[boscoe99]

The red lever being in the off position means that the fuel enrichment function is not working. It should normally be in the automatic position.

Using the fast idle lever to open the throttle only makes a cold start issue worse. You are allowing extra air into the motor at the very time that it already has too much air for the amount of fuel that is available.

If when the red lever is in the automatic position and the motor does not start with several seconds then I would suspect a carburetor issue. When was the last time the carburetors were professionally cleaned and adjusted?

[boham1978]

The previous owner had the entire engine gone through earlier this year.

When I look at the red switch there is only closed and open stamped but the lever physically moves three positions. All the way clockwise is closed, middle is open, and all the way counter clockwise is not labeled with anything.

[boscoe99]

All the way counterclockwise is the automatic position.

Middle position is constant fuel enrichment all of the time.

Clockwise position is no fuel enrichment ever.

[boham1978]

So you're thinking a carburetor issue even though it runs perfect after it does start up?

[boscoe99]

So you're thinking a carburetor issue even though it runs perfect after it does start up?

Yes.

A carburetor is supposed to enable a cold motor to start quickly. That is one of its tasks. It is also supposed to enable the motor to accelerate well and to run at high power settings.

If it is not doing one of its intended functions then it is not working correctly. It needs to be fixed. Otherwise you are putting undue wear and tear on your starter motor.

If you don't think it is a carburetor issue what do you think that it may be?

[99yam40]

Have you thought about what it might do in the normal/automatic position like it is suppose to be run?

Seems you have said you have been running with it in the closed position.

Try it an see before going into the carbs

[boham1978]

Well I'm not a carburetor guy by no means. I'm an electronic technician. I was thinking maybe the PrimeStart coil since that seems to me being the only problem when starting from a cold state. She fires immediately after warming up. Knowing how to properly test it is what I don't know since I don't have specs for the length the needle needs to be as it heats up. It reads 2.5 ohms and power is getting to it when cranking over.

[boscoe99]

Yamaha in their infinite wisdom does not provide specifications regarding the pin extension when the motor is cold versus when it is hot. That I have seen anyway.

When cold, the pin is retracted. Additional fuel can flow to the motor. Once the motor is started electrical power is applied and heats up the primestart device. The pin will extend as the device heats up. At some point the pin is fully extended, stopping flow of the additional fuel. As the device heats up so too do the carburetors. Ideally, when the pin is extended stopping the flow of fuel the carburetors and the motor are fully warmed up such that no additional fuel flow is desired.

As 99Yam40 suggests, try starting the motor with the red knob fully counterclockwise and see if it starts better. If not, try it in the middle position.

[madharchod]

replace your plug may be you have a batch of hot plugs which will give you head ache starting but hot engine no problem

[99yam40]

Well I'm not a carburetor guy by no means. I'm an electronic technician. I was thinking maybe the PrimeStart coil since that seems to me being the only problem when starting from a cold state. She fires immediately after warming up. Knowing how to properly test it is what I don't know since I don't have specs for the length the needle needs to be as it heats up. It reads 2.5 ohms and power is getting to it when cranking over.

normal Start procedure

Turn red lever to normal position and leave it there, pump primer bulb till good and firm, do not lift fast idle lever, hit starter for a few seconds, turn key off of start position for a few seconds, then back to start position again for a few seconds, repeat as necessary till it starts.
Motor should start on second or third , maybe the fourth 3 second roll of the starter

[boham1978]

Well, This morning I turned the lever all the way counter clockwise and fired it up. It took about 30 seconds which is better than it was. So I went about my rat killing (pocket gopher killing for today) for the rest of the day and while I was out in the yard thinking about it, I realized I didn't even pump the bulb to prime the fuel. Knowing I was a dumb @$$, I tried it again (this time pumping the bulb) and she fired after cranking over for a half a second. It had a good 7 hours since I fired it up this morning so it was definitely cooled down.

I greatly appreciate all of your help!

[99yam40]

Glad to hear it works well
Here is a place to read the owners manual for your motor if you do not have one already
Owners Manuals | Yamaha Outboards