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Jeff G.
Jeff G., Marine Mechanic
Category: Boat
Satisfied Customers: 4728
Experience:  42 years experience, Certified Master Technician, All Major Outboards, Sterndrives, Hi-Performance
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I have a 2007 Yamaha f90tlr outboard motor (pontoon boat in

Customer Question

I have a 2007 Yamaha f90tlr outboard motor (pontoon boat in fresh water ) with a continuous alarm at 3000. Engine sputters and won't go above. If at idle for 10 minutes or so will also get alarm. Replaced thermostat, fuel filter, fuel line, fuel/water separator, checked plugs and all look the same with blackened tips (no evidence of blown head gasket ), water comes out pee hole, new battery, high test fuel with yamaha treatment. Engine starts right up. Looked in electrical cabinet with no sign of wire touching or grounding out. Don't know what else to do. Help!
Submitted: 1 year ago.
Category: Boat
Customer: replied 1 year ago.
I also removed thermostat and started engine to see water flow incase of a vapor lock. Water flowed good.
Expert:  Jeff G. replied 1 year ago.

Do you have a tachometer on the boat? What warning light illuminates?

Customer: replied 1 year ago.
I have a trim gauge, fuel gauge, tachometer, and multiple light and accessory switches. There are no warning or dummy lights on the console. I have a 2007 Sedona FS25 pontoon boat.
Customer: replied 1 year ago.
Are you still there?
Expert:  Jeff G. replied 1 year ago.

Is it a Yamaha gauge?

Customer: replied 1 year ago.
Not to my knowledge. There is no indication on the gauges.
Expert:  Jeff G. replied 1 year ago.

Have you checked the oil level? It sounds like the engine is in guardian mode where it cuts the rpm back if the engine runs low on oil, low oil pressure or is running hot. The Yamaha gage has diagnostic/warning lights, which I am asking which tach.

In the future you may want to have a Yamaha gage installed.

Customer: replied 1 year ago.
Oil is full.
Expert:  Jeff G. replied 1 year ago.

Is the oil level above the full mark at all?

Customer: replied 1 year ago.
It looks to be 1/2 inch above the stretch of hash marks on the dipstick.
Expert:  Jeff G. replied 1 year ago.

OK is would appear you are what is called "making oil". Fuel is getting into the crankcase, quiet often particularly pontoon boats or boats used for alot of idling or trolling. This problem can cause low oil pressure. I'd bet if you smell the dipstick it will smell like gas.

What you need to do is drain and refill the oil and change the oil filter. This will raise the oil pressure. The gas in the oil dilutes the oil.

Yamaha recommends the use of Ring Free in the fuel to help keep deposits down and help prevent ring sticking on the pistons allowing the fuel past the piston rings.

Try this and post back your results.

Customer: replied 1 year ago.
Ok I will drain the oil and refill in the morning when I have daylight. Is that ok? Also I originally added Yamaha's ring free gas treatment when I filled the tank several days ago.
Expert:  Jeff G. replied 1 year ago.

Sure just post back at your leisure. I'll be in and out tomorrow but will respond as soon as I can.

Change the filter too!

Customer: replied 1 year ago.
Ok I'll change the filter also. I'm outside of Mansfield, Ohio so it's 12:14 am here. I'll continue conversation in the morning. Thank you
Expert:  Jeff G. replied 1 year ago.

Did you get the oil changed?

Customer: replied 1 year ago.
The engine now makes a "clacking " noise like lifters without any oil. Something isn't right.
Expert:  Jeff G. replied 1 year ago.

Does the alarm still go off? How long did you run the engine with the noise?The crankcase oil is in the crosshatch marks of the dipstick?

Do you happen to have a mechanical (car type) oil pressure gauge. If not you can borrow or rent one from an auto parts store. Put it in place of the oil sender and see what the pressure is.

Customer: replied 1 year ago.
the alarm still goes off. Oil is full at top of hash marks on the dipstick. I ran for several minutes and then engine shut completely down. Still getting clacking sound internally. When I unhook wire from oil sending unit, horn stops. I don't have pressure gauge. I'm afraid to restart because it barley wants to turn over now.
Expert:  Jeff G. replied 1 year ago.

You need to get an oil pressure gauge. Remove the sender and put the gauge in the port and then crank the engine. Remove the spark plugs so it will crank easier and also not start. See if you are getting oil pressure. It's possible the oil pump is faulty.