2003 LZ200TXRB - High /Med Pressure Pmp

[chuckmead]

Runs Good till 2,100 RPM under load, Will not climb any higher,
It has been getting worse, In the past I was able to shut it down then restart it and it would be fine until I idle around then it would act up again when I throttle up.
Boat Mechanic cannot take my boat in for 6 weeks, I have boat trips set up.
Mechanic said its possible that its the high pressure pump.
After reading alot I gather that the High Pressure pumps do not go out, they said to clear the screens and mystery screens that lead to the pump. Any step by step procedures on this anywhere on this forum, I cannot find the screens in the service manuel exploited view, stuck. I do race offroad race cars so I am mechanically inclined, just not on outboards, Looking for step by step help, I heard there are mystery screens and hidden filters to be checked (VST/High Pressure Pump), again motor runs good until 2100 rpm, I have replaced the spark plugs just to be sure, Replaced the first main fuel filter, I imagine the check valve is not a problem, What the next item to check as I get closer to these hidden screens that cannot be found!
Help, thanks,

[99yam40]

Follow your Yamaha service manual procedures for testing to see what and were the problems is.

Monitoring fuel pressures should show if there is a problem with screens/filters and narrow down where

Need to make sure all alarm systems are functioning properly
Just in case something it putting you in safe mode and you are not noticing it

[rodbolt17]

other than the service manual,no step by step.
a bad shift position switch will do that as well.
HP rail pressure can be checked with a multi meter as can the shift position switch.

[Cobia270]

I just sent my high pressure pump out to be fixed. I've read in a couple of forums on how to take apart the pump and replace the filters but I didn't chance it. Flagship marine in Florida is the only authorized dealer to rebuild those pumps.

[chuckmead]

99yam40 and Rodbolt17 Thank you both for helping,
you both solved my last problem.
I do have dual motors to check the existing good motor.

Oil Level alarm ------- tested and good
Temp alarm ------ tested and good
New Spark plugs ------- Replaced and good
New Primary Fuel Filter - no foul in existing filter and replaced - Good

I will test the Shift Position switch tonight,
I want to understand the Shift Position Switch.
Question:
1. Shift Position Switch is be activated and compressed while in neutral and in reverse only - Correct?
2. When Shift Position Switch when activated or compressed, it will limit the rpm under 3000 rpm correct?
3. Any electrical fuses that need to be checked for this Shift Position Switch?

[99yam40]

there is not oil temp alarm, just motor over temp

Shift position switch is to let ECU know when it is in neutral so it can limit RPM while in neutral from what I understand forward or reverse should change it's condition but what do I know. Just guessing

[rodbolt17]

on this particular Z motor the shift position is on at N and off in any gear.
in N it shuts off two cylinders below about 1500,above about 1500 it shuts off 4 cylinders.
if the ECU sees an IN gear signal AND a crank signal it will limit RPM again.

[chuckmead]

okay, that way it will not over rpm in neutral, Forward and reverse it is not limited

Oil Level alarm ------- tested and good
Temp alarm ------ tested and good
New Spark plugs ------- Replaced and good
New Primary Fuel Filter - no foul in existing filter and replaced - Good

I will test the Shift Position switch tonight, and double check (again) the shift cable is adjusted correctly.

[99yam40]

cable adjustment may not be the only problem

[rodbolt17]

ok.
Ill try again.
anytime the shift switch is ON the ECU "thinks" its in nuetral.
this cuts two cylinders.
if RPM goes over about 1500 RPM and the switch is still ON, it cuts 2 MORE for a total of 4.

now
if the ECU sees the switch OFF,it now thinks its in gear.
when the starter is enguaged it sends a 12V signal to the ECU and the start relay.
now, the ECU sees a engine start signal AND an in gear signal.
it knows something isnt right so it limits RPM.
switch failure is rare but it does happen.
can be tested.
thats why the laptop is nice,you can see what the ECU sees.

[chuckmead]

Items Fixed:
Oil Level alarm ------- tested and good
Temp alarm ------ tested and good
New Spark plugs ------- Replaced and good
New Primary Fuel Filter - no foul in existing filter and replaced - Good
Shift Position switch has continuity and is adjusted - correctly - Good

Discussion:
#1. I set & adjusted the Gear shifter with the ohm meter hooked to the switch, while in neutral the switch is on with continuity, while in forward gear switch is off with no continuity and when in reverse switch is off with no continuity, back to neutral switch is on and ohm meter reads continuity. All good

#2. "rodbolt17 mentioned the ECU sees a engine start signal AND an in gear signal.
it knows something isnt right so it limits RPM.
switch failure is rare but it does happen."
#2A. Is this another switch or you talking about the same Shift Position Switch?
#2B. If it is another switch where is it located, If the same switch it looks we are okay per discussion #1 or no??

#3. I wanted to mention when I replaced the 6 plugs, 3 of them were black and 3 were tan.
No Cylinder numbers in service manuel-cannot load pictures
Top Left Cylinder Black Plug
Middle Left Cylinder Black plug
Middle Right Cylinder black plug
All others plugs are tan

[rodbolt17]

when disscussing ANYTHING on a boat we use port and stbd.
this is referenced while in the boat looking fwd the square end at the back and the pointy end front.
that way port is always port and stbd is always stbd no matter if your standing on the dock barking at the moon.

saves a lot of confuzzalations.

z motors.
port top to bottom,cyl 2,4,6.
stbd top to bottom,1,3,5.

cant tell you how many workorders have had me fighting the wrong engines on twins over the years due to this.

its possible you have a bad lift pump or lift pump output.
its possible you have a clogged VST filter.
its possible you have a clogged medium pressure filter.
its possible the filters in the HP pump are clogged.
test medium fuel pressure and HP pressure at the same time UNDER load at the failure RPM.
if HP fails fix the issue between the VST and HP.
if BOTH fail fix the issue between the liquid level in the tank and the VST pump inlet.

[chuckmead]

Items Fixed:
Oil Level alarm ------- tested and good
Temp alarm ------ tested and good
New Spark plugs ------- Replaced and good
New Primary Fuel Filter - no foul in existing filter and replaced - Good
Shift Position switch has continuity and is adjusted - correctly - Good

Discussion:
Updated Information
1. I wanted to mention when I replaced the 6 plugs, 3 of them were black and 3 were tan.
#2 Cylinder Plug - was Black Plug
#3 Cylinder Plug - was Black plug
#4 Cylinder Plug - was Black plug
#1,#5,#6 Cylinder plugs are all tan

[chuckmead]

Items Fixed:
Oil Level alarm ------- tested and good
Temp alarm ------ tested and good
New Spark plugs ------- Replaced and good
New Primary Fuel Filter - no foul in existing filter and replaced - Good
Shift Position switch has continuity and is adjusted - correctly - Good

Discussion:
1. Need help with Vocabulary I feel stupid but now I need to reference these items to the parts in the Service book.
VST = Vapor Seperator T?
HP = High Pressure Pump - Correct ?

2. Is it best to just go and check and clear all the filters below first or is it best to test the medium fuel pressure and the HP Pressure under the loaded rpm first?
Do you recommend me going to purchase a pressure test tool or just clear all the filters and screens?

Recommended listed Items to check:
its possible you have a bad lift pump or lift pump output. (Is this Located in the VST?)
its possible you have a clogged VST filter.
its possible you have a clogged medium pressure filter. (Is this the fuel strainer before it enters the VST?)
its possible the filters in the HP pump are clogged. (Cannot find location of HP Filters in Exploited view in Manuel or parts list on forum? Maybe a Part #?)
test medium fuel pressure and HP pressure at the same time UNDER load at the failure RPM.
if HP fails fix the issue between the VST and HP.
if BOTH fail fix the issue between the liquid level in the tank and the VST pump inlet.
I will check the Pressure Regulator filter as well

[rodbolt17]

why not buy some test eqiupment?
much cheaper than pistons.
why ya gonna dinky dank with a VST pressure regulator?
the money you spend on simple test equipment is worth way more than dinking about.