question on the starting a "2 cycle Merc" sticky

billhig · Jul 19, 2025

I've got a new to me 79 402 2-stroke carb motor that runs great at anything above idle but is difficult to start. I've fixed all the normal things. I don't have a mercury control, so I don't have the idle control lever. I do have the button to advance the throttle without putting it in gear. I have to push that button advance the throttle just to get it to start reliably. I just read the sticky, and I think it says that's the correct way to start it. Have I been beating myself up trying to get it to start reliably without advancing the throttle? Please tell me I stumbled on the right way to start it without knowing it.

Alumarine · Jul 19, 2025

Older 2 strokes have there own ways to start especially cold.
Whatever works is the correct method.
Advancing the throttle by pushing that button accomplishes the same thing as the idle control lever.
You don't mention anything about using the choke?

racerone · Jul 19, 2025

I see so many folks who have little to no understanding how 2 strokes work.----They do start modern cars with the push of a button.-----It is your best interest to learn how to start an older 2 stroke.----Will save lots of time , money and aggravation.

Chris1956 · Jul 19, 2025

Choke the crap out of her when she is cold.

So to cold start her... Advance the throttle, pump the primer bulb until hard, hold the choke button and crank her until she fires. It should take 30 sec or less for her to fire.

billhig · Jul 19, 2025

I use the choke and it starts pretty quickly but dies immediately after starting. If I advance the throttle, it starts and stays running. I thought that was an indication of a problem but the writeup seems to indicate it's normal if you don't have the idle lever.

jimmbo · Jul 19, 2025

Until the Induction System warms up, it will need Spark Advance(that is what controls Idle and Low Speed on these 2 Strokes, not Carb Opening) and an Enriched Mixture to keep running.

racerone · Jul 19, 2025

After starting , if motor falters you push in key momentarily to choke it.-----Do that till motor warms a bit.-----Older motors are simple.----But you must learn the starting method.

Chris1956 · Jul 20, 2025

Gee, It just dawned on me that a lot of the younger generation do not have much experience with chokes, carbs and the like. Push button start auto have been around close to 20 years, and fuel injected cars about 45 years.

So you need to be 40+ to remember pumping the accelerator pedal in your GM, to close the choke and make the mixture rich, before starting it.

Chris1956 · Jul 20, 2025

My '88 Mercruiser had an electric choke. You had to pump the throttle twice to start her. Obviously, marine engines had carbs and points well after autos.

jimmbo · Jul 20, 2025

Chris1956 said:
Gee, It just dawned on me that a lot of the younger generation do not have much experience with chokes, carbs and the like. Push button start auto have been around close to 20 years, and fuel injected cars about 45 years.

So you need to be 40+ to remember pumping the accelerator pedal in your GM, to close the choke and make the mixture rich, before starting it.

I find that to be part of the Entertainment at the Boat Launch...

Nordin · Jul 20, 2025

We in the old generation 50 or 60+have the knowledge about carb engines and how you maybe have to start it and troubleshoot in a logical way. .
The new generation ????
Sad to discover that we will go to a computer troubleshoot generation that will be a random part changer.

billhig · Jul 20, 2025

So good advice, thanks. Also, some comments about the non-choke aware people. Well, I am part of the 60+ generation and having been working on car and bike engines since the late 70's. I've spent my time about carbs and chokes. I spent more time working on 4-cylinder bike carbs than I should have. (got an EFI bike and never looked back). I built a computerized 6 carb flow synchronizer to get my 1966 Porsche 911 running well. So, I get the concept.

The biggest improvement I've gotten is with an ultrasonic carb cleaning - where were these 40 years ago???

I'm brand new to boats and trying to learn how it's supposed to start to see if my engine is within normal or can be improved. The electric choke via the key push releases as soon as I release key so that's a pain. I'll spend some more time fiddling with the manual choke lever on the motor.

jimmbo · Jul 20, 2025

I built an Ultrasonic Cleaner in the 70s, Heathkit

Various Automatic Chokes Systems were devised on some Engines by OMC during the 60s, by the mid 70s, they were discarded and the Solenoid Electric Choke, as used by others, became the Standard Electric Choke

racerone · Jul 21, 2025

And many folks still do not know how to use the wonderful electric primer valve on Johnson / Evinrude models.

Scott Danforth · Jul 21, 2025

billhig said:
The biggest improvement I've gotten is with an ultrasonic carb cleaning - where were these 40 years ago???

ultrasonic cleaners have been around since the 50's, and were widely available in the 80's

racerone · Jul 21, 2025

Agreed----worked at a plant over 50 years ago.----Heavy duty ultrasonic cleaner.----Made the fluid dance when it was turned on.

That old Mercury · Jul 21, 2025

billhig said:
I've got a new to me 79 402 2-stroke carb motor that runs great at anything above idle but is a ***** to start. I've fixed all the normal things. I don't have a mercury control, so I don't have the idle control lever. I do have the button to advance the throttle without putting it in gear. I have to push that button advance the throttle just to get it to start reliably. I just read the sticky, and I think it says that's the correct way to start it. Have I been beating myself up trying to get it to start reliably without advancing the throttle? Please tell me I stumbled on the right way to start it without knowing it.

Make sure motor is trimmed all the way down.
Pump up bulb tight, with key switched on push in key for 5 seconds , pump up bulb again choke for 5 seconds. Push in your throttle button and move it about 1" forward. Thier is a sweet spot on the throttle you will have to find .
Like other have suggested when it cranks and tries to die choke it some more.
If you use it in colder months below 50 degrees you will have an even worse experience!

racerone · Jul 21, 2025

On a 79 model 402 why would you push in the key for 5 seconds with key turned on ???

That old Mercury · Jul 21, 2025

racerone said:
On a 79 model 402 why would you push in the key for 5 seconds with key turned on ???

Because i am an idiot !

Captain Caveman · Jul 21, 2025

Chris1956 said:
Gee, It just dawned on me that a lot of the younger generation do not have much experience with chokes, carbs and the like. Push button start auto have been around close to 20 years, and fuel injected cars about 45 years.

So you need to be 40+ to remember pumping the accelerator pedal in your GM, to close the choke and make the mixture rich, before starting it.

I'm a hair away from 50. My first cars were carbureted. The first truck that I bought had carb issues, so I installed a manual choke and a push button start. So much fun.

However, after buying it I could figure out how to turn on the highbeam headlights. I was 20-something and a 60yr old saw me trying to figure something out while I was sitting at the gas station. I told him that I couldn't find the high beams, and of course he said, it's the button on the floor!

Some day we'll be teaching the young kids about how to use an old cell phone or a computer mouse.

question on the starting a "2 cycle Merc" sticky

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