Nissan 3.5 4 stroke hard to start

[RainDog]

My Nissan 3.5 4 stroke used to start easy on first pull. I would pull out the choke, start it, then after a few seconds, push in the choke.

It now is very hard to start. Requires full choke, then many pulls. Once it starts, I have to let it idle with at least half choke for a long time; up to several minutes. If I push the choke in before this, it dies.

Once it gets warmed up, it runs normally and has no problem at any RPM. Tried a new spark plug already. The outboard has no (replaceable) fuel or oil filter.

Any idea what I should try next?

[Sailor Doug]

How much fuel stabilizer are you using? Had big problems with a Yamaha 4hp. Liberal use of conditioner solved issue.


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[a64pilot]

Clean the carb, your idle circuit is beginning to clog, causing it to be a little lean,
Or you have a vacuum leak, which would also cause a lean mixture, but most likely the carb.


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[RainDog]

I was not using stabilizer, but will start. Will clean the carb tomorrow. Thanks.

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[MarkSF]

The best way to prevent this is to run the carb dry after use. Stabiliser helps, so does just keeping the gas fresh. When it gets a few months old, i pour it into the car.

[Sailor Doug]

Running a four stroke dry will try a sailors patients. I run mine dry at the end of the season. Disconnect fuel hose (never used internal tank) cruise around the marina for awhile trying to stay within rowing range, eventual the motor runs out of fuel and stops. It would be even longer at idle. Fuel sipping one of the few good things about a Yamaha 4HP.


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[DeepFrz]

RainDog, how did you make out with the OB?

[RainDog]

Cleaned carb and it is much better. Still dies at idle. I think I will replace the low speed jet and see if that solves the issue. But at least now it is easily usable, so cleaning the carb was a huge help. In hindsight, for $40, I should have rebuilt the carb instead of just cleaning it. I had the kit, was just being cheap.

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[Therapy]

Originally Posted by RainDog

Cleaned carb and it is much better. Still dies at idle. I think I will replace the low speed jet and see if that solves the issue. But at least now it is easily usable, so cleaning the carb was a huge help. In hindsight, for $40, I should have rebuilt the carb instead of just cleaning it. I had the kit, was just being cheap.

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I left a 6 hp merc with a shop and the guy said with the newer motors he won't even try to do anything related to hard starting, stalling till he puts a new carb kit in it. I am too cheap.

I used SeaFoam. Inject into carb till it stalls. Let sit. Repeat. Usually takes a couple or a few times.

Tried to put an image and why I can never get it to work is beyond me.