nissan 9.9 4 stroke hardly runs

[Jamin Kauffman]

I’ve got a 2002 Nissan 9.9 4 stroke.When I bought it it would idle awesome and run up to half throttle then die.Took to very good marine ship and they cleaned the carb(and charged an awful lot!)Had it out Saturday and ran like a dream,never a studded.Today,Tuesday,started on first pull and revved up to full throttle about 4 times with it in gear (ran for about 10 sec at full throttle)as I was doing some manual trim adjustments,and after that it just started sputtering.Could start it after that but not rev up.Now can’t start at all,or when it does it’s just for a few seconds.Has gas:/primer bulb is hard,vent is open.Has automatic choke.What now?kick it?Thanks

 

[pvanv]

Year is irrelevant. Model is critical. I assume yours is an NSF9.9A or B.
It does not have automatic choke. It has a solenoid (ABS) for auto enrichment.
Are the plugs wet or dry? Wet is no spark or flooding; dry is lack of fuel.
Check to make sure the ABS solenoid is working, and confirm the passage in the bottom of the bowl that feeds the accelerator pump is clear.

 

[Jamin Kauffman]

Okay thanks I will check!The only problem is I can find no model or serial number whatsoever.I’ve looked every where in it and the only number is on a freeze plug(serial number?)

 

[Jamin Kauffman]

Just an update...cleaned carb very thoroughly and also noted their was no gasket on intake manifold where it bolts to the block???is that normal?I made a gasket for it and put it on.Runs perfect in the barrel I just have to try it in the river

 

[pvanv]

The number on the soft plug is the serial.
There should be a metalized mylar label with both model and serial, unless someone removed it.
Yes, you need a manifold gasket.

 

[Jamin Kauffman]

There is absolutely no label anywhere saying what model no.Any idea how to figure out?Also motor still acts up some times at wot.When I take fuel line off carb,it will squirt about twice when I yank rope than stop but bulb is still fairly firm.It doesn’t squirt hard at all so y’all think it might be my fuel pump?I did find a hole in my fuel line that helped a lot when I fixed it

 

[pvanv]

What makes you think the motor was manufactured in 2002, if there isn't any label?
It is possible for an under-performing fuel pump to limit top end, but more common is a leaky fuel line or o-ring or pickup in the tank.
If you have the line off at the carb and pump the bulb, do you get fuel?

 

[Jamin Kauffman]

It has a label on the side that says my 2002.Has no model no on it.Yea fuel shoots thru hose when I pump bulb.I filled tank all the way n it still did it.Had to keep pumping bulb to keep running at top end than I noticed a lot of gas in oildoes that come from pumping bulb or is there another issue?

 

[Jamin Kauffman]

I’m thinking that fuel pump is leaking straight into the valve cover,is that possible?when I squeeze the bulb when under power I can make it firm then it suddenly goes about half flat than firms up again etc.I did check fuel pressure and it’s about 7 so it should be good?also remove intake manifold and it’s not wet inside after running.Im really ticked at this motor and I would just take it to the marina again but their busy and I need this motor now.Any help is appreciated.Thanks!

 

[Jamin Kauffman]

O and I forgot to say that when it’s bogging down when trying to advance throttle and when running at anything above idle,I can put my fingers over the air vent for a bit and it immediately smooths up (choking it).It seem as tho the fuel pump works for a minute or so than just quits

 

[pvanv]

Pull the fuel pump and prime and see if the diaphragm is leaking.
The emissions sticker just means that it passed 2002 emission standards... nothing else.
If you call the serial in to Tohatsu in Dallas, they can look up your model and year of manufacture.

 

[Jamin Kauffman]

Ok guys I’m still here:/I’ve replaced the fuel line and pump.Cleaned the carb very,very thoroughly(I tried).Motor idles just fine,will run at half throttle for about 30 sec. than start to die,if I put my fingers over intake it will rev momentarily which causes me to still think carb.It also make oil a lot which I can’t understand with the new fuel pump which shouldn’t be leaking,and it doesn’t run rich cause it idles fine.Any ideas?is there something electronic that could be causing this.Any help would be greatly appreciated.I must admit I don’t fully understand the abs,what would be the symptoms if that was bad?thankyou

 

[pvanv]

You should go through the carb again. The abs heats and the needle expands, leaning the mix. Full info is in your Factory service manual.