60HP 4 stroke cutting out @5K RPM

[VirtualBoater]

I have a 4 year old Yamaha 60HP High Thrust 4 stroke on our pontoon.

The motor starts great and runs great. But after about 4 minutes of 4-5K RPM running it starts cutting out. If I throttle down for a bit, then back up, I can go again for another few minutes, etc.

The white plastic housing that holds the internal fuel filter appears clean. The boat has a quart sized filter mounted to the boat, which I can't figure out how to get off, but if I disconnect the fuel line, stick a plastic wedge in the ball and pump the prime bulb, I'm getting plenty of fuel squirting out. The bulb refills quickly when I let go.

The motor has less than 40 hrs of use and I've always used Non-Oxy gas with it.

Any idea what's wrong? Fuel pump? At $100+/hr for labor at the Yamaha shop, I'm not against shot gunning a fuel pump or something else in it for a few bucks.

Thank you for any help.

[panasonic]

I have a 4 year old Yamaha 60HP High Thrust 4 stroke on our pontoon.

The motor starts great and runs great. But after about 4 minutes of 4-5K RPM running it starts cutting out. If I throttle down for a bit, then back up, I can go again for another few minutes, etc.

The white plastic housing that holds the internal fuel filter appears clean. The boat has a quart sized filter mounted to the boat, which I can't figure out how to get off, but if I disconnect the fuel line, stick a plastic wedge in the ball and pump the prime bulb, I'm getting plenty of fuel squirting out. The bulb refills quickly when I let go.

The motor has less than 40 hrs of use and I've always used Non-Oxy gas with it.

Any idea what's wrong? Fuel pump? At $100+/hr for labor at the Yamaha shop, I'm not against shot gunning a fuel pump or something else in it for a few bucks.

Thank you for any help.

Is the engine peeing alright? What RPM does the engine drop to? (if you have a tach) Do you have enough oil in the engine?

Sounds like it is going into RPM reduction mode which is sensing low oil pressure OR overheating (not enough cooling water)

[panasonic]

Is the engine peeing alright? What RPM does the engine drop to? (if you have a tach) Do you have enough oil in the engine?

Sounds like it is going into RPM reduction mode which is sensing low oil pressure OR overheating (not enough cooling water)

[panasonic]

Is the engine peeing alright? What RPM does the engine drop to? Do you have enough oil in the engine?

Sounds like it is going into RPM reduction mode which is sensing low oil pressure OR overheating (not enough cooling water)

Do you have a tachometer with warning lights (Yamaha multifunction gauge)?

Can you look at the engine when running at high RPM and see if it is still peeing?

[99yam40]

I would monitor fuel pressure and vacuum to make sure all of that is good before throwing parts at it

by the way what is oxy gas, E10?

[pstephens46]

Have you tried pumping that primer when you are having issues? That would point to a lp fuel problem also...

[TownsendsFJR1300]

Your quart sized fuel filter is similar to an automotive oil filter (but for fuel)

Some are water separators as well.

To remove, put an filter type strap wrench around the base of it (regular threads) and spin it off.

It's also not uncommon for the smooth gasket surface on the mount itself, to corrode. Make sure it's smooth, the old gasket removed before spinning a new one on (with a touch of oil on the gasket (just like a car filter).

I'd also dump it in a container and check for debris/water..

[panasonic]

But after about 4 minutes of 4-5K RPM running it starts cutting out

You have a Tachometer...do you mean it drops down to say 2500 RPM and stays there?

Or it just starts to misfire, bog down, rpm all over the place?

[VirtualBoater]

Have you tried pumping that primer when you are having issues? That would point to a lp fuel problem also...

Haven't tried, would like to, but no safe way to do it with the configuration. There's the motor, then about 12" of deck, then the railing and then seating. So there's not enough room for me to be out on the deck while the boat is under way and the fuel hose isn't long enough to reach into to the boat.

I'd be afraid of pumping it then having the motor take off and I go flying over it. LOL!

[VirtualBoater]

Is the engine peeing alright? What RPM does the engine drop to? (if you have a tach) Do you have enough oil in the engine?

Sounds like it is going into RPM reduction mode which is sensing low oil pressure OR overheating (not enough cooling water)

Good thought...I should explain what it's doing better. The motor starts cutting in and out, like turn a light on and off every second. It's not dropping RPM and staying there. So it's like full throttle, cut ignition, full throttle, cut ignition, repeat about once a second.

The oil on the dip stick is only slightly off of fresh brown, and is half way between the top and the bottom of the crosses on the dip stick.

My old outboard had an audible alarm on the remote and in the motor, do these new outboards not have audible alarms.

[rodbolt17]

does it have an audible?
depends on who rigged it and with what rigging.
most blow boaters run the rigging to cheap then whine about it.
tell us what it is rigged with.