I have a 1992 Overnighter with a 2004 Yamaha 150. It bucks and looses power when trying to plane or just run faster. It seems ok at idle and low speed. I have replaced all fuel parts (gas filter, separator) including some hoses. I checked all cables and cleaned making sure its not a ground wire issue. The voltage gauge drops down when it bucks but not sure if this is due to losing power. I will say I noticed this problem ever so slightly when i put boat in in May and it got worse as season went on. I filled tank with fresh gas and added Strarbright Gas treatment, Very frustrating
Grady 1992 Overnighter
- Thread starter federig1
- Start date
What voltage does the gauge show when the motor is running OK and when it bucks?
It could be a bad electrical connection. If the voltage swings between 12.5 or so and 13, it is probably not a bad connection. If it swings between 13 or so and something low, like below 11, you probably have a bad connection somewhere.
More likely is a fuel issue but you may need to put a fuel pressure gauge on the fuel rail to see.
It could be a bad electrical connection. If the voltage swings between 12.5 or so and 13, it is probably not a bad connection. If it swings between 13 or so and something low, like below 11, you probably have a bad connection somewhere.
More likely is a fuel issue but you may need to put a fuel pressure gauge on the fuel rail to see.
I am leaning towards an electrical issue also because it was so intermittent. Last season I was cruising the Manasquan River with family and hit a rough wake, I reached my destination but on the return trip i noticed a slight performance issue. Thank You
Doc Stressor
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Have you ever changed the VST filter over all those years? The symptoms you describe are typical of a clogged VST filter. Even if that is not the cause of your issue, it's time to change that filter. It takes a bit of work, so if you aren't handy or have the time, have a shop do it.
Seasick explained what to look for if you have a true voltage issue. The most common cause is a loose or corroded ground connection either at the boat's ground stud or where the heavy black wire connects to the starter.
Seasick explained what to look for if you have a true voltage issue. The most common cause is a loose or corroded ground connection either at the boat's ground stud or where the heavy black wire connects to the starter.
Here's a dumb question:
When was the last time you changed the plugs? Spark plugs make a world of difference, especially in an outboard.
While the plugs are out is a good time to do a compression test
Lt.Mike
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To me it would sound like a fuel delivery issue. Either a blocked line, filter or jet for a carbed engine or injector.
If you run out of the Manasquan your in my neighborhood.
Where the river is freshwater and stocked with trout it runs through my backyard.
If you run out of the Manasquan your in my neighborhood.
Where the river is freshwater and stocked with trout it runs through my backyard.
Spark plugs just changed, we are cables from batt switch to engine. The existing ones feel brittle from raising and lowering engine, as you know they are together in a harness
Ok, sounds good. Also there is an anti-siphon valve at the fuel tank connector. They do go bad.
Another possibility is the run the boat with and auxiliary gas tank. Connect one of those portable five gallon fuel tanks and see how she runs on that.
This is how I found out my anti-siphon valve on my 93 Adventure was bad
Good luck, keep us posted
Fixed ! We
We found bad cables from engine to battery switch. Wires were hard and brittle behind engine...Thank all for responding