Popping and shaking

[NissanOutboard]

I’m new to old outboards.

My engine seems to be popping and shaking a tad when using muffs.

Any ideas as to what this might be?

 

[Scott Danforth]

start by cleaning your fuel system

you are running lean

 

[NissanOutboard]

start by cleaning your fuel system

you are running lean

Sorry for my ignorance here - Fuel System meaning -- Fuel Pump, Carb, and Fuel Lines?

 

[Scott Danforth]

Sorry for my ignorance here - Fuel System meaning -- Fuel Pump, Carb, and Fuel Lines?

and fuel tank

 

[Bobbywolf]

What you are seeing is referred to as a lean sneeze. It could be the carbs out of adjustment, partially blocked with dirt and varnish, or lack of fuel delivered to them.

 

[NissanOutboard]

Here is an update -- I changed the fuel filter, cleaned the carb, and checked that fuel is flowing well from the tank to the filter.

The motor is still running with a lean sneeze. Any chance it could be an issue with the air/fuel mixture screw?

 

[QBhoy]

Personally always found chasing assumed issues with an outboard on muffs and not in its natural state of operation, can be end up in hours you’ll wish you had back later in life !

 

[Scott Danforth]

Here is an update -- I changed the fuel filter, cleaned the carb, and checked that fuel is flowing well from the tank to the filter.

The motor is still running with a lean sneeze. Any chance it could be an issue with the air/fuel mixture screw?

How do you clean a carb and not remove the air/fuel mixture screw.

Please explain how you rebuilt it

 

[NissanOutboard]

I pulled the carb off. Took off every piece - jets, nozzles, screws, air/fuel screw, float, float valve. Sprayed them all with carb cleaner and made sure all holes and carbon was cleaned off. Used compressed air on all holes. It was surprisingly clean when I pulled it all apart. I guess the last owner had torn it down also.

I was just thinking maybe the fuel/air screw might be out of adjustment. I’m a novice so maybe I’m just missing something. Please let me know if I’m making an error here.

 

[dingbat]

Not sure about the lean pop diagnosis

Sounds and looks (puffs of smoke) like a dead miss

 

[NissanOutboard]

Dead miss meaning missfire?

Would that be related to a timing issue?

 

[NissanOutboard]

Hi fellas,

I pulled the plugs today that are only a week or so old. Here is what they look like…

Seems to me I might be running rich..what are your thoughts?

 

[QBhoy]

It could also be that you are getting a weak ignition. That will cause similar on the plugs and running like it is. Have you checked your stator/regulator output and coils ? Easier is to put a meter on the battery if she has one

 

[NissanOutboard]

I have not checked. No battery on it right now just using the pull starter.

Any links to a good resource to learn how to check stator, regulator, and coils?

 

[racerone]

How does it run when boat is floating in water?-----Use a timing light to look for an ignition miss if there is one .----Perhaps throttle plates open too early.----Have you tried adjusting low speed mixture screw?----Thermostat in place and working properly ?

 

[QBhoy]

I have not checked. No battery on it right now just using the pull starter.

Any links to a good resource to learn how to check stator, regulator, and coils?

Have a wee YouTube search. Easy enough to check. Will be an AC output to the regulator and DC after that. Likely be around 18v AC going in and should be upwards of 13v DC out…with some rpms on her. Best with a multi meter that has the diode function of possible

 

[QBhoy]

Or if it has a charging outlet on it..put a meter across those cables and see (with meter set to DC).

 

[NissanOutboard]

How does it run when boat is floating in water?-----Use a timing light to look for an ignition miss if there is one .----Perhaps throttle plates open too early.----Have you tried adjusting low speed mixture screw?----Thermostat in place and working properly ?

Haven’t had a chance to take it out on the lake. Just got it 3 weeks ago have been working on restoring the hull and getting the motor up to speed. I have not tried adjusting the low speed mixture screw - I’m not sure where that screw is located…any help?

Also I’ll check the thermostat tomorrow and get back to you about that.

 

[NissanOutboard]

Have a wee YouTube search. Easy enough to check. Will be an AC output to the regulator and DC after that. Likely be around 18v AC going in and should be upwards of 13v DC out…with some rpms on her. Best with a multi meter that has the diode function of possible

Sounds good just ordered a multimeter — ill get back to you with what it tells me

 

[QBhoy]

Sounds good just ordered a multimeter — ill get back to you with what it tells me

Ok. Just be careful and make sure you’ve looked into what you are going to do. You can get a fair smack off it if you’re not careful. Test your coils too. That’s just a resistance on the meter. Likely set to 200ohms range usually…if it’s not an auto range meter. There will be a specific tolerance reading for your coils at a given temperature that you need them to achieve. Also easy to do. Very handy tool to have for a boat too.