F20 startup issue +video

[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.

[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.

[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]

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

[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

[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!

[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]

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]

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

[99yam40]

If the screw is not set tight, it will move with the vibration of motor running.
that pin hold screw was not meant to be a float adjusting screw on any carb I have ever seen

[merc200dalarna]

If the screw is not set tight, it will move with the vibration of motor running.
that pin hold screw was not meant to be a float adjusting screw on any carb I have ever seen

I don't think it is either. But I can't do anything else. Unless I had a new one to compare with. But it is impossible to screw it down, it raises the back end of the float way high ( from the measuring point on the carb body). So now I will go for a float check instantly if I run into fuel issues again. It's like max 3 weeks left of the boat season here, this will have to do for now. =)

[pstephens46]

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!

Yam, Scott, Roscoe (but not Rodbolt) or someone can confirm. That pump should pump regardless of the float height, correct? Plunger moves as long as the engine is running.
Would a faulty float setting affect the fuel filter filling with fuel? I believe the fuel loops in the F150 as far as the VST float needle being closed. Not sure about this F20.

[pstephens46]

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

Do you ever chase the wife around the house with those needles?

[TownsendsFJR1300]

Yam, Scott, Roscoe (but not Rodbolt) or someone can confirm. That pump should pump regardless of the float height, correct? Plunger moves as long as the engine is running.
Would a faulty float setting affect the fuel filter filling with fuel? I believe the fuel loops in the F150 as far as the VST float needle being closed. Not sure about this F20.

For the carb, that screw should NOT be loose (as posted earlier). There is a clip, part #14, that may be installed in correctly:

2006 and Later F20MLH Yamaha Outboard CARBURETOR Diagram and Parts

Loosening that screw is simply dropping the float level. It is NOT meant as an adjustment. There should be a small metal tang On the float by the pin) that you can adjust (bend slightly to spec's) to adjust the float height (while the carb is upside down). I've had carbs with a piece of crap in-between the seat and the needle causing havoc too...

The fuel pump is AFTER the filter assembly and before the carb. I've never seen a return line with a carb, I suspect there's either simply low pressure (say 15 PSI) or a regulator (not likely). The carb needle ALONE should be enough to close off incoming fuel once the bowl is full..

That engine is NOT FIXED and will eventually get you stranded once that screw vibrates out and the engine floods...

As for the fuel pump Pat, looking at the parts diagram, I don't think that pump is MECHANICALLY driven like the F150, but vacuum (IE, engine must be running to pump). I might be missing something in the pic's but most of the little engines use vacuum(I could very well be wrong).

But he has fuel NOW, the carb still isn't right... Have to get the basic's down first before moving to other issues..
.