2013 20hp four stroke no power in drive can't plane!!

[Jacob13217]

Hey guys I don't know what else to do. I have a 2013 Yamaha 20hp four stroke on a 14' aluminum Lowe boat. The boat cannot plane with one person it it. It is so slow sonetsome has to be wrong. But it starts idles and runs so smooth.... I thought the prop might be too tall so I went from a 10 to an 8 pitch... The boat does the exact same thing. Not one bit better. I cleaned the carb... Squeezed the primer ball at full throttle.. ran fresh gas... It has to be electric. Can anyone help me where to look next plz see video

https://youtu.be/LQRTARxUE-8

[panasonic]

Sounds like it may be in RPM reduction mode..won't go past 2500 Rpm. Low oil pressure switch or overheat switch may have failed.

Do you have a Service Manual? These switches are easy to test if you have a manual.

Please post exact model and serial number from data plate on transom bracket so we may be able to help you find the problem.

[Jacob13217]

I've read about that. I don't see a temp or oil might iluminated so I thought it couldn't be. But I'm puzzled so any help would be great see attached image of data plate. Thanks for the help folks. I appreciate it

[TownsendsFJR1300]

There's 3 different models of that engine but it does have a thermo-switch, part # 29: https://www.boats.net/catalog/yamaha...7/electrical-1

When you revved it in neutral, it didn't sound like it was getting up to full RPM. The RPM's don't sound like it's hitting even 3,000 in forward gear.

Have you checked to make sure the throttle is OPENING FULLY at WOT?


Lastly, is the boat new to you? Has it ever planed out normally before? Has the engine sat for a long period of time?

[panasonic]

I've read about that. I don't see a temp or oil might iluminated so I thought it couldn't be. But I'm puzzled so any help would be great see attached image of data plate. Thanks for the help folks. I appreciate it

Yes you are correct one of those two lights on the front of the engine pan should be lit up if you have low oil pressure or over temp conditions. However I have replaced a couple of those warning light assemblies on two F15 in the past, light burnt out.

Have a close look at the two little led's and see if they look the same, they should look alike. If one is dark it maybe burnt out.

I am not saying this is your problem...just a possibility. Easy to test the rpm reduction system and rule it out.

[panasonic]

Your manual should be here.

https://www.vansoutboardparts.com/se...0&limitstart=0

[Jacob13217]

I have checked throttle linkage adjustment it is opening fully. The boat is new to me I got it 2 years old with the purchase of our cottage. It's never been right. But I didn't know any better until I used my friends Honda 20hp and it flew. The boat has never worked as it should as long as I've owned it.
it sits in a heated garage all winter (Ontario Canada) and gets used every weekend in summer...

I'll have to check the rpm reduction system and report back. If there are any other tests you folks figure I should run, I'd appreciate them also!

[99yam40]

Have you pulled the plugs and inspected them to see if one is different color or fouled?

how about compression or leakdown test of cylinders to make sure they are sealing well?

check timing to see that it is in spec and advancing as it should.
do both plugs have good spark even when problem shows up

Need more fuel to make power and also need the timing to advance

could be possible the prime start enrichment system is not working and it runs too rich when warmed up.
manual will have test for that also

Does this motor have a lever to turn the system to off,manual on, and automatic?
if so where is it set to?

[Jacob13217]

I have pulled the plugs .They both look good and brown. They both spark well. How can one check the timing advance on this motor? I have not worked on an outboard this new. There is no lever on my motor for manual auto and on.. I won't be at my cottage for a few more days. But I'll bring my multimeter and test the systems listed here and report my findings

[99yam40]

A standard timing light hooked to plug wire will show what the timing is doing, just like on an automotive motor.
Have you looked in owners manual to see if says anything about your prime start system?
I know very little about that 4 stroke motor but the 2 strokes had a way to turn them on and off along with automatic

[rodbolt17]

no way to turn the system on or off. it is what it is and most times works.
I have seen the LED's fail. I have seen the CDI box fail and the timing not advance.

[Jacob13217]

How can I test and rule out the cdi is in fact advancing the timing rodbolt? They are like $600 cad .So I'd like a proper diagnosis before spending that kind of money

[99yam40]

have you thought about seeing what the timing is actually doing with a light?

[Jacob13217]

I am familiar with using a timing light to set base timing and such... But what am I looking for to see that timing is in fact advancing...

[robert graham]

Try running motor with upper cowling removed...a plugged air intake or an inside cowling exhaust leak could make motor run sick...