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Charles
Charles, Marine Mechanic
Category: Boat
Satisfied Customers: 3370
Experience:  US Navy (Ret) Certified Mercury Marine Tech with over a decade of repair experience.
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Stalls under light load. Good on hose but in water good at

Customer Question

Stalls under light load. Good on hose but in water good at idle and wot but not a light load
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Customer: Replaced the port side head due to hole through spark plug threads and changed bottom coil same side because spark would bite you but still runs the same
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Customer: No
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Submitted: 7 months ago.
Category: Boat
Expert:  Jason replied 7 months ago.

Hello my name is ***** ***** am I speaking with?

What are we working on?

Customer: replied 7 months ago.
My name is*****'m working on a 1990 yamaha 225. 225etxd
Expert:  Jason replied 7 months ago.

Hi Brandon.

What is the history on this engine? Have you ever personally seen it make full power?

Have you done any spark or compression testing on your own yet?

Customer: replied 7 months ago.
Not sure if i have seen it full power. Had one issue when it was WOT for a little ride and lost forward momentum for a couple minutes but was fine ever since. I bought it about a year ago and haven't really had many issues. New OEM NGK plugs all coils now firing and compression is 120 +/- 2 psi
Expert:  Jason replied 7 months ago.

You have good compression, and you say spark is good. The next step would be going through the carbs and rebuilding them. Has that been done yet?

Customer: replied 7 months ago.
No it hasn't was next course of action. Why would it be fine on the hose though? I'm an auto mechanic but not familiar with outboards or 2 strokes
Customer: replied 7 months ago.
You know I did start noticing one thing that I thought was not good. When I put it in reverse and gave it a little throttle the motor shook pretty good like it was misfiring
Customer: replied 7 months ago.
Last time I took it out we anchored on an island for a couple hours and when we were ready to leave it wouldn't start until I sprayed it with starting fluid then would only idle then after a little while was able to WOT but not light throttle.
Customer: replied 7 months ago.
Also is there a way you can tell me the test procedure for the tps
Customer: replied 7 months ago.
Sorry but another thing I noticed was on my fishfinder it would sometimes show almost 17 volts
Expert:  Charles replied 6 months ago.

Hello, my name is***** you still need assistance with this engine?

Customer: replied 6 months ago.
Expert:  Charles replied 6 months ago.

Ok, First thing that we need to verify is that voltage on the battery with the engine off and then with it running at idle and then at about 2000 RPM. I am looking to see if it is getting over 14.5V DC and the reading on the fish finder is correct when it shows 17V.

Customer: replied 6 months ago.
Well the tps connector was corroded so I rewired it. That took care of the stalling. But now when it's WOT for like 30 secs it will bog down to idle for a couple seconds then I can take off again. Haven't had the chance to check voltages yet
Expert:  Charles replied 6 months ago.

Does the alarm test beep when you turn the key to on?

Are your oil tanks full?

Do you know how old the water pump is?

Customer: replied 6 months ago.
No alarm test beep. Oil tank full but bypassed. Not sure on the water pump seems to piss ok. My gauges don't work either. Is it hard to hook up analog gauges to a yamaha?
Expert:  Charles replied 6 months ago.

Do you currently have digital gauges?

Customer: replied 6 months ago.
I do but you can hardly see what they are displaying. The numbers are real faded
Expert:  Charles replied 6 months ago.

Analog gauges really do not work for this engine. You would not have the oil pump fill function.

Customer: replied 6 months ago.
Ok. So what do I do next?
Expert:  Charles replied 6 months ago.

Test the horn circuit for the engine. It should have power in with the key on, but will only have a ground for a few seconds. If that works, replace the warning horn. We need it working to know if you are getting an alarm at WOT or not.

Have you looked into the carbs yet?

Customer: replied 6 months ago.
Ok i will. Do you have a diagram? And I haven't yet I will do that also
Expert:  Charles replied 6 months ago.

For the wiring or the carbs?

Customer: replied 6 months ago.
Wiring for the alarm not sure where it is. Only reason I haven't gone through the carbs is because it idles and cruised ok and will even take off and get up to speed nicely just after a minute or less it bogs down
Customer: replied 5 months ago.
Was gonna try to do some trouble shooting when I get home. Will the buzzer go off if it's over heating or something like that?
Expert:  Charles replied 5 months ago.

Provided that it is still functioning, yes it should.

Customer: replied 5 months ago.
Ok and if the voltage is true to 17v what next?
Expert:  Charles replied 5 months ago.

If the voltage is really at 17V, the regulator would be bad.

Customer: replied 5 months ago.
Ok i tested the buzzer wiring. Key on the yellow wire gets battery voltage and the pink gets 6 volts. I unplugged it and put power and ground and buzzer didn't work but I got it to work but still doesn't get ground
Expert:  Charles replied 5 months ago.

The buzzer should only get a ground when there is a fault on the engine.

Customer: replied 5 months ago.
What about the test beep though?
Expert:  Charles replied 5 months ago.

Yamaha has changed it over the years, some have it, some do not, Hard to tell which does and which dont..

Ever do the running test for the voltage at the starter solenoid?

Customer: replied 5 months ago.
Will do tomorrow
Expert:  Charles replied 5 months ago.

ok

Customer: replied 5 months ago.
I decided to pull the carbs and go through them. Is there any specifications you know on the adjustments when putting them back together?
Expert:  Charles replied 5 months ago.

Set your mixture screws at 1 1/4 turn out for starters, you may need to adjust them once the engine is in the water and at idle.

Customer: replied 5 months ago.
What about float adjustments? I found one lower then the other in the first carb
Expert:  Charles replied 5 months ago.

Have it running and make small adjustments to it.

Customer: replied 5 months ago.
You can't adjust floats without taking the bowl off
Expert:  Charles replied 5 months ago.

The floats need to sit level with the body of the carb.

Customer: replied 5 months ago.
The alarm is going off now I'm on the boat
Expert:  Charles replied 5 months ago.

That is either oil level in one of the tanks or overheat, or voltage. Unplug the head temp sensors and see if it stops..

Customer: replied 5 months ago.
There is never oil in the tank
Customer: replied 5 months ago.
It stopped when I unplugged the sensor
Customer: replied 5 months ago.
When I take off the port side it doesn't stop buzzing. Only on starboard side
Expert:  Charles replied 5 months ago.

Either that head is hot, or the sensor is bad.

Customer: replied 5 months ago.
Well it slows down and smokes
Customer: replied 5 months ago.
White from exhaust and boggs down
Expert:  Charles replied 5 months ago.

It is going into protection mode. That is why it is slowing.

Customer: replied 5 months ago.
if it's over heating on one side. What do you think it is?
Customer: replied 5 months ago.
Voltages to spike at times
Expert:  Charles replied 5 months ago.

If the voltage is spiking it is the regulator that is going out.

Customer: replied 5 months ago.
I removed both thermostats
Expert:  Charles replied 5 months ago.

The engine needs the stats to operate properly. Otherwise it will not come up to temp.

Customer: replied 5 months ago.
Just want to see if the buzzer will go off
Expert:  Charles replied 5 months ago.

Ok

Customer: replied 5 months ago.
Still doing it
Customer: replied 5 months ago.
Water pump?
Expert:  Charles replied 5 months ago.

Is the head hot to the touch? Is the sensor still plugged in?

Customer: replied 5 months ago.
Yea I plugged it in and could hold my hand on head for a second or 2
Customer: replied 5 months ago.
if it was the sensor I don't think there would be white smoke though. Unless that's from it going in a limp mode
Customer: replied 5 months ago.
Maybe I'll put the sensor on the other side tomorrow and see what happens
Expert:  Charles replied 5 months ago.

Provided that they are the same sensor, that would work.

Customer: replied 5 months ago.
Swapped the sensors and still buzzing for starboard side
Expert:  Charles replied 5 months ago.

You are going to heave a blockage inside the water passages on that head. You will need to open it up and inspect it.

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