Need help troubleshooting Yamaha 250 hdpi

[gretchenfalk]

Can anyone help with spark plug info and cylinder info. I know that at idle only 4 cylinders are firing, which ones? When I tested the plugs it seem that only three are working at idle.
Also on two of the spark plubs I smelled gas (the bottom plug of each side).
Also there was loss of power at high rpm and now there is a ticking sound coming from the starboard side of the motor.
I found a little dirty fuel in the first fuel filter and a little more in the one on the side of the motor.
The motor is 2003 one of the first off the assembly line (never do that again, live and learn... has blown up twice in 6 years and was covered under warranty but no more)Any advise would be greatly appreciated. Thanks in advance.

additional info make z250txrb serial no 60vx1001035

Call Yamaha and found the numbering of the plugs.
Facing the motor from the stern forward they are 1 bottom right 2 left, 3 middle right 4 left and 5 top right 6 left. It so happens this motor has blown twice before and the issues were with the number 1 and 2 cylinders.
Those are the ones I smell gas on and the middle two are a little wet with oil.

 

[yamamarinetech40]

Re: Need help troubleshooting Yamaha 250 hdpi

I'm of course thinking Yamaha is last to blame for your troubles, considering you have trashy fuel in an outboard(type, being HPDI) that everyone knows HAS TO HAVE CLEAN FUEL. You can NOT run these motors on trashy fuel, your book tells you this in many places. And you have the plug #'s wrong(1 is top right, then 3 then 5, 2 is top left, then 4 below and 6 below that....the fact that Yamaha covered the repairs before says nothing, since Yamaha doesn't say no, I've seen them cover stupidity many times, even motors never being flushed and plugged up with salt(twice).
Ok, anyway, you would be helping yourself to get compressions on all cylinders before anything else(no sense trying to fix two bad ones(if), and then take VST off engine and clean out, check injector's spray patterns(esp. on those two wet plugs), and fuel pump output. I can't remember whick plugs die at idle, but remember that if idle is high or you advance throttle in neutral, it'll drop more(additional). How big is loss of power? Are we talking 500 RPM or 2000?
I want to say #1 and #4 and then #2 and #5 will drop, but just can't remember, books aren't here now. These are picky engines, but if taken care of they are awesome. Also don't forget the expensive filter inside VST tank that you've probably ruined if you have trash in first filter.

 

[gretchenfalk]

Re: Need help troubleshooting Yamaha 250 hdpi

I'm of course thinking Yamaha is last to blame for your troubles, considering you have trashy fuel in an outboard(type, being HPDI) that everyone knows HAS TO HAVE CLEAN FUEL. You can NOT run these motors on trashy fuel, your book tells you this in many places. And you have the plug #'s wrong(1 is top right, then 3 then 5, 2 is top left, then 4 below and 6 below that....the fact that Yamaha covered the repairs before says nothing, since Yamaha doesn't say no, I've seen them cover stupidity many times, even motors never being flushed and plugged up with salt(twice).
Ok, anyway, you would be helping yourself to get compressions on all cylinders before anything else(no sense trying to fix two bad ones(if), and then take VST off engine and clean out, check injector's spray patterns(esp. on those two wet plugs), and fuel pump output. I can't remember whick plugs die at idle, but remember that if idle is high or you advance throttle in neutral, it'll drop more(additional). How big is loss of power? Are we talking 500 RPM or 2000?
I want to say #1 and #4 and then #2 and #5 will drop, but just can't remember, books aren't here now. These are picky engines, but if taken care of they are awesome. Also don't forget the expensive filter inside VST tank that you've probably ruined if you have trash in first filter.

Thanks for the input even with the sarcasm.
What can we do about the quality of the fuel we get?
As for the number of the cylinders I guess it isn't important but the info I got was from the yamaha rep over the phone. We have a tech coming out to day.

 

[yamamarinetech40]

Re: Need help troubleshooting Yamaha 250 hdpi

Yeah, sorry for sarcasm, but I don't like shots at Yamaha, when I know lengths they go to for quality customer experience.....the only things you can do for fuel problems(quality);
1. If your boat is trailerable never ever buy gas from marinas...it's almost always much older than the local shell station's, and today's formulations don't last long. Also, the fuel tanks are usually surrounded by water as much as dirt and if it's salt, well.....
2. Try to keep the fuel rotated in and out of the boat on regular basis, not putting in five times as much as you'll use in a month(for instance).
3. Empty the fuel water seperator mounted in boat(if you don't have one, GET ONE) on a monthly basis or every 15 hrs. of use.
4. Replace the engine mounted(one in see thru cup) with a 10 micron filter ONLY on HPDI, and do this every 50 hrs. This filter isn't expensive and keeps the high dollar ones clean.
Don't know type of boat you have, but if fuel vent is on side of boat, I'd consider doing away with it and installing hose/kit for vented cap(may already have, if already there, check gasket.
Tech may run shock of ring free to clean injectors....I would reccoment that.

 

[gretchenfalk]

Re: Need help troubleshooting Yamaha 250 hdpi

Thanks for the input.
I have been treated fairly by Yamaha but do think it would have been better if we waited for the bugs to be worked out before purchasing this motor.
We had recalls and spent a lot of money on oil and spark plugs prior to being told to go to a bk6 plug.
We have had warranty work done and the wrong plugs put in more than once.
Enough of that story it doesn't matter now.
Here is what we found. Good compression. Yes!
Good ignition. Yes!
VST Filter Good no trash. Yes!
The tech thinks we need to run the boat full out more.
He cleaned out the plugs and blew out the gas and oil, took it for a test run and it ran fine.

We are going to have to change the filters more often and not do so much trolling with out running harder.

We will take your advise and get those filters changed. But we did put a new on on both filers recenlty. Maybe we got a bad batch of gas the last time we filled up.

Just for you information we have a Pathfinder 24' puchased in 2002 but it is a 2003 model and the Hpdi is 2003 as well.

 

[yamamarinetech40]

Re: Need help troubleshooting Yamaha 250 hdpi

Try to stay away from marina gas, don't know if your 24 is marina or not...and if you empty the fuel water seperator in boat enough, you wont have to change the filters as much....and it is a big thing to run ANY 2 stroke or 4 stroke, 2 strokes cause they run 20 degrees colder than 4 strokes, 4 strokes because they run cool compared to car engines and can't boil crap outa oil....glad it all turned out good. NICE BOAT by the by

 

[gretchenfalk]

Re: Need help troubleshooting Yamaha 250 hdpi

I don't know if I should post here or not.
We are having more plug problems and we have been keeping up with the filters so I don't think it is that.
Plugs are fouling, oil on the plugs.
New plugs fouled after one half day charter.
Took the plugs out, blew out the cylinders and put plugs back in, boat ran fine for another half day trip.
Now stalling at idle and plugs are wet again.
Model z250txrb serial no. 60vx1001035.
Thanks in Advance for any help.

 

[gretchenfalk]

Re: Need help troubleshooting Yamaha 250 hdpi

We are booked solid this week and need help now!
Please is anyone on line that can help.

 

[rodbolt]

Re: Need help troubleshooting Yamaha 250 hdpi

ok, in nuetral this motor is designed to run on 4 cylinders below about 1800 RPM and on 2 cylinders above about 1800 RPM. this is controled by the shift position switch. if out of adjustment or defective its always triggered and RPM is affected in or out of gear.
you will need some basic test equipment and a certain amount of general knowledge and some electronics knowledge.
start by testing the lift pumps. then by checking the medium pressure output at the VST it MUST maintain about 50 PSI at ALL times.
you will need a minimum of a digital voltmeter to test high pressure fuel at the sensor or better the YDS setup on a laptop.
O-P should be 3.2V minimum at all engine speeds.
what I would do is test compression and spark at cranking, compression should be within 10 PSI on all six and spark capeable of jumping a 7/16ths gap.
from there you will need the tuneup spec guide as a minimum to test the sensor outputs.
normal problems we have is the VST filter and the inline medium pressure filters stopping up and reducing fuel pressures causing an excessivly wide fuel pulse width.
check your engine seriel numbers for the latest oil pump update,your pump arm should have a 60v3, out of memory check with your dealer, on the pump arm.
we actually didnt have many issues with that engine after the first oil pump and ECU update in 04, make sure yours was done.
have you checked the plug caps. there are many things that can go wrong on that engine, a faulty crank position sensor,have you tested yours for both resistance and proper output with a peak reading type meter?
the engine temp sensor can give faulty but in range feedback that will cause a rich fuel mix.
incorrect throttle shutter sync can create issues as well.
while the HPDI seems complex its really fairly simple,you just have to break each engine subsystem into their subsystems and find out whats not there.
its also why I have 3 digital meters,2 DVA adapters,2 CD-77 meters,3 counting the one in venezuela, and the mercury analog multi-tester with a DVA function avalible at most any place that sells seirra branded marine products.
but start with the basics that anybody can do to eliminate dumb stuff that even experienced techs get tripped by.
check the tech bulitens on how to PROPERLY check/set the gap on the EKU style plugs. there are 2.
biggest issues we have had are faulty fuel systems and bad ful. the engine mechanically seems to work well but is very intolerant to fuel system issues as are the Optimax and the E-tec.
my personal 07 175 E-TEC tossed #4 rod through the block at 15 hours but I had had it 1 1/2 years.
I suspect it had a fuel issue but the dealership said no and 9 days later I had a new fully dressed powerhead.
but without a minimum of an understanding of how the systems work and a minimum amount of test equipment your mostly at the mercy of a dealership.
find one that has at least one master tech employed and demnd that techs attention.