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Brand New 30HP EFI Nissan - Having Problems

Copperhead305

New member
I just purchased a brand new skiff a couple months ago.
I picked it up April 14th.
I used the boat regularly.
One day I was out on the water, and out of no where the motor began to shake and shut off.
It did this for about 10 minutes.
Then out of no where it kicked back to life and ran perfectly fine.

I figured it was just a random occurrence because it happened shortly and ran perfect afterward.

A few days later I went out again and I Idled all the way out the channel and once I put got out of the no wake zone, the motor began to shake.
Once I hit the throttle to jump on plane, the motor shut off.
It kept doing this.
A friend of mine had to drive 2 hours to the keys to pick up his boat then drive back up to go and drag me back in to the ramp (which by now was 4 miles away. Got to thank AT&T for having great service).

I checked the fuel filter and there was some white slush in there.
I emptied out all the gasoline in the gas tank and refilled with brand new gas and an E10 additive.

By now, the motor wouldn't start up.

I cleaned out the spark plugs and put them back in and the motor fired right up and ran good on the water hose.

So I took it to the local lake and the moment the outboard was under a load, the motor shut off.

I loosened the screw at the bottom of the bowl on the electronic fuel pump and let out the gas that was inside and then the motor ran great.

I ran the boat at the lake and it ran great for about 15 minutes.
Then the power completely dropped.
The RPM's shot down, and the max speed at WOT dropped to 20mph.

I emptied out all the gas again, and this time fueled up with Non-Ethanol 89 Octane gasoline.

I went out and the motor ran perfect for another 15 minutes and then back down to 20mph.
Then out of no where, the RPM's dropped again, and the max speed became 10mph.

I loosened the screw at the bottom of the bowl to let out the gas and did it again.
The motor got the power back up to 20mph, but only for about a minute.
Then the RPM's would drop back down and would run at around 10mph.

One can feel the motor trying to get power and run, it just isn't getting the power.

Checked the pressure at the fuel rail and it was showing 40psi.

I was told it should be at 30psi.
That the high pressure fuel filter inside the fuel pump could be a little clogged, causing it to shoot gas faster into the injectors but without enough volume.


Someone at Tohatsu had recommended we run some Seafoam through it for 45 minutes and see if it cleans it out.
I did that, but it fouled up the spark plugs.
I had to clean them up and it still doesn't run more than 10mphs at WOT.
And the RPMs are low.
I want to get this problem fixed ASAP.
And I have checked three different Tohatsu/Nissan local dealers, and all of their mechanics are on vacation.
It's incredible how lack of service there is for these outboards in South Florida.


It's a brand new Nissan Marine 30hp EFI.
It doesn't even have 20 hours on it.

I have a Tohatsu water fuel separator installed on the fuel line as well.
 
Service on a 25/30 EFI is best done by someone with a Factory service manual, a diagnostics harness connected to a laptop PC running the Tohatsu 3AC diag software), and good general mechanical skills. This powerhead is identical to the Nissan and Mercury, so hopefully you can find a hired wrench to work with you, especially since you are still under warranty. Too bad you aren't located on the Great Lakes... would love to help you out, but the travel expenses would be obscene... ;-(

The white slush you found in the fuel system is a good clue, and may be the root of all this. That can happen with E-10 gas, stabilizer, and water combined. Lacking any diagnostic capabilities, I would suggest completely flushing out the entire fuel system. You could use compressed air to blow out the old fuel, then charge with fresh fuel, and blow it out again to hopefully push out any remaining junk. BTW, that slush can be corrosive to aluminum parts. Also, FWIW, contaminated fuel is typically not covered by warranty.
 
I figured it wouldn't be covered by warranty, but it's hard enough to find a tohatsu mechanic down here.
I still can't believe that the only three tohatsu mechanics are all on vacation.
 
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