Nissan won't idle/Help identify please

[YN2(SS)]

Trying to help a friend with a Nissan 4 stroke, Mod NSF4A 3H9-1 and Ser 11450.

1) What year and hp is it?

2) It won't idle and will only run at higher RPM. It jerks when put into gear (at higher RPM).

I am guessing the carb is dirty and needs rebuilt. Idle circuit clogged. I have experience with old Johnsons and 30 yr old mercs, but not new Nissans. Is a carb rebuild on this o/b pretty standard. I haven't looked at the motor yet.

3) Where can I get a carb rebuild kit?

Thanks in advance for your help!

 

[pvanv]

Re: Nissan won't idle/Help identify please

This is a current Tohatsu/Nissan 1-cyl 4-stroke 4-hp. Same block for the 4/5/6 series. You need to thoroughly clean the low speed circuit in the carb. Parts are available at any Tohatsu/Nissan dealer. Elvin has a parts catalog at http://www.internetoutboards.com/PartsCatalogMenu.htm BTW, manufacturing year is not important -- the model is. But if curious about the exact year, you can contact the factory by using the "Contact Us" link at http://www.nissanmarine.com/

 

[YN2(SS)]

Re: Nissan won't idle/Help identify please

PVANV,

Thank you very much for the response. Idle circuit was what I was thinking. When I rebuild, what mixture screws have presets and where could I find out what those presets might be? Also, do I set the idle mixture with the outboard in the water idling, in gear? Thanks!

 

[pvanv]

Re: Nissan won't idle/Help identify please

The idle mixture "pilot screw" (see the parts catalog on Elvin's website) at http://www.internetoutboards.com/PartsCatalogMenu.htm comes from the factory with a plug covering it to satisfy the EPA. In order to do a thorough cleaning, the idle screw will have to come out, which means drilling out the plug to get at it. If in doubt about your skills with the drill, have an expert do it for you.

Count the precise number of turns required to gently seat the screw, and that will be where you will want to reset it after cleaning. Yes, if you need to adjust the idle mixture, it would be done at low idle, in the water, under load.

BTW, a common carb culprit in these very-lean-running motors is clogging of the emulsion tube (or "nozzle"). Sometimes that can be cleared with spray carb cleaner, but it's always more thorough to do a soaking in Tyme or similar submersion cleaner, and then blow out with air. Just remember to completely disassemble everything first, as the submersion cleaners will destroy any plastic bits.

 

[YN2(SS)]

Re: Nissan won't idle/Help identify please

PvanV,

Again, greatly appreciate the response. Carb kit is on the way and this looks pretty straightforward!

John

 

[YN2(SS)]

Re: Nissan won't idle/Help identify please

OK, found the o/b laying on it's side in the owners barn, crankcase oil leaking out of the spark plug hole where the plug had been removed. I have on order the following:

1) carb kit
2) water pump kit
and have asked the owner to get some engine crankcase oil and lower unit oil when picking up the kits this week.

The carb is off and I completely disassembled it, removing all parts that were not metal. It is soaking in a basket in carb cleaning solution. One little problem though:

When I was drilling the EPA plug out to remove the idle mixture screw, the drill bit touched the top of the idle mixture screw, turning it in until it seated.


So, I again need the find what the idle mixture preset is.

Also, what is the correct quantity of oil for the crankcase and do I drain and fill the lower unit in a manner similar to most other lower units (Johnson, Eska, Mercury, etc.)?

Any answers GREATLY APPRECIATED!!!!

Thanks!

 

[pvanv]

Re: Nissan won't idle/Help identify please

Ugh. You may have (likely did) inadvertently damaged the low speed mixture needle and/or seat. If you're lucky, they lived through the torque. Very easy to hurt the tiny jet. Start with the screw at about 2 turns out, and see what happens. Then adjust from there.

At worst, you will end up buying a new carb. You can interchange the 4,5, and 6 hp carbs onto this motor, so if you want a boost in power, the carb for the 6 is a good setup.

Crankcase oil capacity is about a pint. Fill it until a little below the "full" mark on the dipstick. Be patient, as the level takes a few minutes while the oil is settling into the cam gears and oil pump, to read correctly. Do not overfill, not even a drop. Use non-synthetic 10w-30 4-stroke OB oil (not just automotive type), as it has better corrosion additives.

The LU is filled with both plugs out, until the lube comes out of the top hole. Then install the top plug, then install the lower plug. Just like other OB's.

 

[YN2(SS)]

Re: Nissan won't idle/Help identify please

Paul,

Again, can't thank you enough for your response. I am optimistic about the idle mixture screw. When I removed the plug, I attempted to turn the screw clockwise to see where it was at, and it wouldn't turn. Then I saw a little "hit" on the top of the screw from one of the smallest drillbits that I used. Turned it counterclockwise and it turned very easily, like it wasn't even seated. I will critically look at it.

Again, thanks!

John

 

[YN2(SS)]

Re: Nissan won't idle/Help identify please

Follow up on the idle mixture screw incident. I inspected it after removing it and all looked fine. Preset it at 2 turns and once in the water, all worked well in setting the idle. next time I am going to drill through a 1" by 1" block of wood and then cut the block of wood to length, exposing only the last 1/8" of the bit to prevent this from happening again. Thanks all for your help!