[jreddin]

I recently purchased this used engine. The engine fired and ran on the stand at the dealer. Ran all cables and rigging for the engine. On muffs the motor ran and the impeller was working. Took the boat to a local lake where the fired and ran perfectly. This lake has a speed restriction, but I was using it simply to test the engine for shifts in and out of gear (forward and reverse), and basic performance. I felt the motor was running fabulous, and decided to head to the boatramp to transport to a larger lake to really open her up. About 30 yards from the ramp the engine lost fire. It then would not restart. Back at home I checked the plug wires for spark using a screwdriver, but nothing. Any ideas?

[rodbolt]

when you turn the key to ON can you hear the fuel pump run for about 5 seconds. are you positive the alarm buzzer works ?

[jreddin]

Yes, I do hear the fuel pump running. The only alarm I have heard is when I try to start the engine with the kill switch lanyard pulled.

[rodbolt]

if the pump comes on the main relay is working.
if you get no alarms when cranking the ECU is not seeing a stop signal.
it uses an alenator driven ign system with 6 pulser coils and a charge coil for each bank.
I really cant think of an easy solution to a no spark on all six other than test the inputs to the ECU and the outputs from it.

[jreddin]

Just how do I test the inputs and outputs?

[rodbolt]

you will need the tune up spec guide at a minimum and a peak reading meter.
you can do some tests with an ohm meter and look for open circuits.
carefully test all grounds, especially the ground for the timer assy. all 6 pulser coils share a common ground.
if you actually have lost spark on all 6 cyl we need to go look at what is common to all 6. and that is about it.
the ECU will ,or is supposed to, automatically go into default if the ECU has a failure or low voltage. with the key on,test all orange wires for 5V.

[jreddin]

How often do cdi/ecu failures occur? I do not have a ohmmeter, but I am afraid that it might be my problem.

[jreddin]

Oh I forgot, is there a diagnostic software available for my engine?

[rodbolt]

no soft ware.
but for about 70 bucks you can buy the diagnostic lamp. in your case a DVM with a DVA adater will be better money.
ECU/CDI failures are right up with UFO sightings.

[jreddin]

In order to use the lamp, does the engine have to be running? Also I am not not familiar with what a DVM with a DVA is. I am new to boats, sorry.

[rodbolt]

the engine only needs to be cranking to retive codes and some codes only require ign on.
a DVM is a digital voltmeter and is avalible from any radio shack for 25 dollars or so. the DVA is a peak reading adapter most DVM's have the ability to use a 50 dollar DVA adapter. the CD-77 meter is very good but its 269 dollars or so.
you can get an idea of the conditon of the stator and pulser coils with a DVM set on the Ohms scale and the tune up spec guide.
its odd to lose spark on both banks , the only thing common is the stator inputs, one for the port bank and one for the stbd and the pulser coil assy which all 6 coils share a common ground path, thats where I would start hunting, that and dissconecting the kill circuit.

[jreddin]

I finally broke down and took the boat to a shop with a cert. yamaha tech. I just hope that he can get me back on the water for not alot of $$. Will post results of the techs findings. Thanks for the help.

[jreddin]

My mechanic says it is the stator not producing enough volts. Does that sound like a possibility? I have told hime to fix it, and I hope it works.

[rodbolt]

like I said, the pulser assy shares a common ground path for all six trigger inputs to the CDI. if the ground wire fails or the connection get dirty,loose or corrded you get no trigger inputs and no CDI outputs.
so yes a faulty pulser assy can create a no spark condition as can a bad ground path.
on that engine a stator failure normally drops one bank not both.
at least the pulser is one of the cheaper parts on your engines ign system.

[jreddin]

I am still waiting on my mechs final verdict, but you have been a tremendous help rodbolt.

[jreddin]

The stator assy. fixed the no spark problem, but now I cannot get the motor to idle. We can get the motor on plane after a long hesitation. Full speed works very well. It appears that the oil pump is oiling way to much. We used two of the internal reservoirs in about 1 mile on the lake.

[rodbolt]

sounds like ya need a real tech.
miles have no meaning on a marine application.
depending on engine RPM the system will oil between about 130 to 1 to 50 to 1.
above about 3000 its fifty to one or approx 2.6 ounces of oil for every gallon of gas, at WOT that motor can eat 25 gallons an hour with ease.
but if the engine oil tank is overflowing due to a switch failure or improper service or reassemby it will overflow into the air box and the bottom cylinders swim in oil.
if the oil control rod is dissconected for any reason the pump will deliver its physical maximum limits.
but you have other issues as well I am thinking.
post the engine model number so I can verify what fuel/ign system you have.
and try to find a shop near you that has at least one master tech or at a minimum look for the electrical and fuel systems course completion stickers on the techs diploma from yamaha, if this is not a factory trained tech dont let him touch a 250.

[jreddin]

It is an L250TXRV. I know he is a certified yamaha tech. I just don't understand why the engine ran perfectly well from 8am until 1pm. At that time the alarm sounded and I shut it down, pretty abrubtly because I panicked. After pulling the engine cowling I noticed the oil reservoir empty. I added oil and after that it would not idle. It will run wide open, but it struggles to get fuel, but then will get up to speed.

[jreddin]

Will the test lamp tell me if my engine is oiling too much? Also what is the part number for the test lamp?

[rodbolt]

no it will not,
how did you fill the engine oil tank ?
and is this machine correcrtly rigged with yamaha parts ?

[jreddin]

It is rigged with yamaha parts and we filled it on the internal reservoir by opening the top and pouring it into the tank. We filled it up to the top mark on the reservoir.

[rodbolt]

did you retrieve the seal on the filter and replace it with a new one as per the service nabual? did you line up the vent marks on the filter to float switch?
why did you not allow the automatic transfer or at least toggle the emergency switch?

[jreddin]

I do not have the external oil tank hooked up. I have one but it is still in the box. I have not changed the seal on the filter. What will happen if the marks are not lined up on the filter to float switch. Will it cause over oiling? What does the seal prevent?

[rodbolt]

the seal prevents trash on the tank bottom from entering the pump, the vent,if not properly lined up will allow overfilling.
if you will notice the filter does not have a screen for the first 1 inch or so, thats to give a margin for trash and water.
my advice would be to go ahead and rig this machine properly,catch up on any maint issues like pumps,VST filters, O2 sensor output tests and maybe even flushing the injector filters.
if you keep messing about you will post about a knocking or loss of compression.
if the seal is not retrived its possible to mash it down the tank to pump hose and shut off oil to the pump.
I see 2 or 3 each year that inccorect maint was worse than no maint.
the OX66 225 was a very solid motor, it wont tolerate inccorect maint or running conditions.
it is more than willing to pop a piston if something is not right with the fuel or ign system.
the oiling system is almost bullet proof if the correct procedures are followed.

[jreddin]

I will begin the preventative maint., but someone asked me why dont I bypass the oiling system and just mix my oil and gas. Is that a possibility? Or is it just a stupid thought?