F20 startup issue +video

[merc200dalarna]

Boat: https://imgur.com/a/escZY

[merc200dalarna]

Yes I thought the pump needed to be ruled out. If we confirm it's pumping correctly then we are pretty much back to carb. I suspect that is the case....like I mentioned before, those pump parts are tough.

Where do you source those needles? How long are they?

And the pump test is what lead me to the float. It was a good test. I did it twice infact, the first time it filled up instantly, and the second took about 2 minutes and some revving before it filled it up completely.

Thank you all for all the help, I'm 99% sure it was solved with the float height!

[merc200dalarna]

Did you not have trouble with the float and needle in a separate post awhile back? I wonder if that float is still not right and sticking....

Also make sure the fuel tank is venting properly (I am assuming you are using a 5 gallon portable tank) You can loosen the cap while running and the engine is acting up, see if it starts running right.These new tanks only vent one way and that sometimes don't work right.

Seems strange that it will run good when warmed up but keeps cutting out when it is cold...but now you say it is losing power at WOT as well....

What kind of boat is it? Could not see the whole thing in your video.

Did you not have trouble with the float and needle in a separate post awhile back? I wonder if that float is still not right and sticking....

Also make sure the fuel tank is venting properly (I am assuming you are using a 5 gallon portable tank) You can loosen the cap while running and the engine is acting up, see if it starts running right.These new tanks only vent one way and that sometimes don't work right.

Seems strange that it will run good when warmed up but keeps cutting out when it is cold...but now you say it is losing power at WOT as well....

What kind of boat is it? Could not see the whole thing in your video.

Mister Panasonic, you are a better detective than Sherlock himself. Most likely it was the darn float again. I did the filter bowl test, and it took so long before it eventaully filled up the cup (fully filled). Made me think that it couldn't really pump until float opened to let more in. Anyway I looked at factory specs of float height (15mm) and it was way off. And yes, in my last post I could see that if I tightened the screw at the pivot needle of the float, the float raised up. But I was told I should seat the screw, so I did. But today I softened the screw until the float reached spec. Starts and runs.

I will add one more short video on youtube that shows how unresponsive the throttle is and wether I can (not necessarily need) "jet up" to perhaps F25 jets? Around size #60 and about #125? Mostly because I love this tinkering with things. But still, the throttle response is not at all good.

The boat is an ordinary swedish fibreglass 15ft (4,7 meters), 220kilos, called "Hoga Rodd 470" or "HR 470". After downpropping to 10 pitch I reach 17-18 knots with 2 adults and fishinggear. Pic of my boat will be inserted in a seperate post, it won't let me post.

Above all, thank you all again!

[merc200dalarna]

Did you not have trouble with the float and needle in a separate post awhile back? I wonder if that float is still not right and sticking....

Also make sure the fuel tank is venting properly (I am assuming you are using a 5 gallon portable tank) You can loosen the cap while running and the engine is acting up, see if it starts running right.These new tanks only vent one way and that sometimes don't work right.

Seems strange that it will run good when warmed up but keeps cutting out when it is cold...but now you say it is losing power at WOT as well....

What kind of boat is it? Could not see the whole thing in your video.

Mister Panasonic, you are a better detective than Sherlock himself. Most likely it was the darn float again. I did the filter bowl test, and it took so long before it eventaully filled up the cup (fully filled). Made me think that it couldn't really pump until float opened to let more in. Anyway I looked at factory specs of float height (15mm) and it was way off. And yes, in my last post I could see that if I tightened the screw at the pivot needle of the float, the float raised up. But I was told I should seat the screw, so I did. But today I softened the screw until the float reached spec. Starts and runs.

I will add one more short video on youtube that shows how unresponsive the throttle is and wether I can (not necessarily need) "jet up" to perhaps F25 jets? Around size #60 and about #125? Mostly because I love this tinkering with things. But still, the throttle response is not at all good.

The boat is an ordinary swedish fibreglass 15ft (4,7 meters), 220kilos, called "Hoga Rodd 470" or "HR 470". After downpropping to 10 pitch I reach 17-18 knots with 2 adults and fishinggear. Pic of boat:https://imgur.com/a/escZY
Above all, thank you all again!

[merc200dalarna]

Did you not have trouble with the float and needle in a separate post awhile back? I wonder if that float is still not right and sticking....

Also make sure the fuel tank is venting properly (I am assuming you are using a 5 gallon portable tank) You can loosen the cap while running and the engine is acting up, see if it starts running right.These new tanks only vent one way and that sometimes don't work right.

Seems strange that it will run good when warmed up but keeps cutting out when it is cold...but now you say it is losing power at WOT as well....

What kind of boat is it? Could not see the whole thing in your video.

Mister Panasonic, you are a better detective than Sherlock himself. Most likely it was the darn float again. I did the filter bowl test, and it took so long before it eventaully filled up the cup (fully filled). Made me think that it couldn't really pump until float opened to let more in. Anyway I looked at factory specs of float height (15mm) and it was way off. And yes, in my last post I could see that if I tightened the screw at the pivot needle of the float, the float raised up. But I was told I should seat the screw, so I did. But today I softened the screw until the float reached spec. Starts and runs.

I will add one more short video on youtube that shows how unresponsive the throttle is and wether I can (not necessarily need) "jet up" to perhaps F25 jets? Around size #60 and about #125? Mostly because I love this tinkering with things. But still, the throttle response is not at all good.

The boat is an ordinary swedish fibreglass 15ft (4,7 meters), 220kilos, called "Hoga Rodd 470" or "HR 470". After downpropping to 10 pitch I reach 17-18 knots with 2 adults and fishinggear. Pic of boat:https://imgur.com/a/escZY

Above all, thank you all again!

[99yam40]

the reason for using soft copper wire is to keep from distorting the brass jet orifices.
they are not just holes, so important not to damage the shape

[panasonic]

Friendly neighborhood physiotherapist gives them to me..they are about 4" long.

[pstephens46]

Did you not have trouble with the float and needle in a separate post awhile back? I wonder if that float is still not right and sticking....

Also make sure the fuel tank is venting properly (I am assuming you are using a 5 gallon portable tank) You can loosen the cap while running and the engine is acting up, see if it starts running right.These new tanks only vent one way and that sometimes don't work right.

Seems strange that it will run good when warmed up but keeps cutting out when it is cold...but now you say it is losing power at WOT as well....

What kind of boat is it? Could not see the whole thing in your video.

Yes I thought the pump needed to be ruled out. If we confirm it's pumping correctly then we are pretty much back to carb. I suspect that is the case....like I mentioned before, those pump parts are tough.

Where do you source those needles? How long are they?

[panasonic]

Service manual was helpful in removing the plunger and diaphragm for the first time. There is a pin. Pump is similar to the two on my F150. Be sure to check your oil level to make sure the fuel is not getting past diaphragm into the head and crankcase. There is a second diaphragm on the other side of pump. It has a clear membrane. I guess that could leak pressure also. Two check valves in metal body in between the two. All of these parts looked to be pretty robust in my 12 year old motor.

Don't be afraid to use some thin copper strands on those passages in your carb. Fishing line or plastic may not do the job.

I use acupuncture needles for poking jets and carb passages. I have two sizes .010" and .007" They work good.

[panasonic]

Did you not have trouble with the float and needle in a separate post awhile back? I wonder if that float is still not right and sticking....

Also make sure the fuel tank is venting properly (I am assuming you are using a 5 gallon portable tank) You can loosen the cap while running and the engine is acting up, see if it starts running right.These new tanks only vent one way and that sometimes don't work right.

Seems strange that it will run good when warmed up but keeps cutting out when it is cold...but now you say it is losing power at WOT as well....

What kind of boat is it? Could not see the whole thing in your video.

[TownsendsFJR1300]

The engine should be turned OFF.

You want the cup emptied, re-install, then start the motor and watch the cup fill. It should stay that level when running.

My FI'ed engine, cup, stays around 2/3's full normally..

Make sure that cup and seal are FULLY SEATED when installed...

Ethanol tends to expand the cup, making installation tight.

[pstephens46]

Yes! Stop the motor. Take bowl off and empty. Put it back on and start motor.
Observe....

[merc200dalarna]

The cup, part #7: 2006 and Later F20MLH Yamaha Outboard FUEL 1 Diagram and Parts

simply unscrews from the mount. There is a small red ring (floats if water is in there). as well as an O-ring seal at the top. The "unit" inside is your under cowl, fuel filter...

Stick a rag under there just so your not spilling fuel under there....

I know I took it fully apart last winter, it all looked fresh then. I will be on the lookout for the red ring and o-ring. Should I stop the motor and then restart it with the cup emptied? Or should I do it while running?

[TownsendsFJR1300]

The cup, part #7: 2006 and Later F20MLH Yamaha Outboard FUEL 1 Diagram and Parts

simply unscrews from the mount. There is a small red ring (floats if water is in there). as well as an O-ring seal at the top. The "unit" inside is your under cowl, fuel filter...

Stick a rag under there just so your not spilling fuel under there....

[merc200dalarna]

Don't panic........I was simply stating that sometimes the diaphragm will fail and allow fuel past into the engine. I am not saying that is your problem. But it needs to be monitored if you think there is a fuel pump issue.

The oil level will rise in the oil pan as it starts to be diluted by the fuel getting past the diaphragm. The oil level will read abnormally high. Way past the point that you last filled it. Strong smell of gas in the oil.

It would seem strange that the diaphragm would fail in your 4 year old motor.

Have you ever removed the clear plastic bowl on the fuel filter? Dump the gas out of that bowl after the motor is good and warmed up. Put the bowl back on and watch to see if it fills back up. Fairly rapidly, maybe 10 seconds? That would at least show you the fuel pump is indeed pumping. It may not fill to the top of the bowl. As long as it rises to 3/4 it should be fine. Post a video if you wish.

That seems like a pretty straight forward test.Can I unscrew it without loosening the bolt on top? Empty the gas out of it and screw it back and see how fast it refills!
Awesome advice.

Yes, the motor is very fresh, overall. I have used it 140 hours.