200HPDI yamaha possible fuel issue

[johnnyrob]

Hi Legends and Gurus, went out on our typical offshore all day trip motor started missing about an hour out , i immediately checked water seperator on inline filter and it was full of water, I check this prior to any trips, attitude of boat obviously changed pickup in tank cleared this and carried on, motor cleared and ran fine rest of trip, until coming back up harbour started missing again, have since put a new inline filter in, but was still missing under load when I tried it nxt, so have changed the in fuel filter on the motor as it was very dark in the fins compared to a new one, so yet to retry it out, been told to maybe change the spark plugs, but theyre less than 20hrs old, but thought I might put the old plugs back in just to be sure, Would really appreciate any advice on what else I could potentially do or check as nothing worse than have a trip organised only to have to cancel because of something like this! The motors never let me down in the 10 plus years Ive had it and the boat was only serviced 20hrs ago, Thanks Again

[99yam40]

need to open up system and check for water in it everywhere.
water in the system and filter you found it in does not mean it did not make it into the rest of the system.
that tank still has water in it if it hit the filter, it did not go away that easy

[Keithbaja]

Welcome to ethanol fuel or water intrusion to your tank. Do the same process. complexly drain and clean tank. It should have access cover. Then drain fuel all fuel from tank to motor install new w/s with fresh gas, fill the w/s also with fresh fuel. Use primer bulb to get fresh fuel on the last filter on motor under the cowl. Cycle key several times and try starting. If no go find the 2 stroke starting spray and get her up and running... DO NOT let sit with water in the fuel system..
few hrs work. Finding 2stroke starting fluid may take the most of your time. And you may not need it. Good luck

[johnnyrob]

need to open up system and check for water in it everywhere.
water in the system and filter you found it in does not mean it did not make it into the rest of the system.
that tank still has water in it if it hit the filter, it did not go away that easy

Thanks for the feedback, havent found any water in water separator since, so hoping water in fuel tank is no longer an issue when you say everywhere, does that mean I should replace the filter in the VST and the medium pressure filter on top of the motor besides the prior 2 filters ive replaced? cheers.

[johnnyrob]

Welcome to ethanol fuel or water intrusion to your tank. Do the same process. complexly drain and clean tank. It should have access cover. Then drain fuel all fuel from tank to motor install new w/s with fresh gas, fill the w/s also with fresh fuel. Use primer bulb to get fresh fuel on the last filter on motor under the cowl. Cycle key several times and try starting. If no go find the 2 stroke starting spray and get her up and running... DO NOT let sit with water in the fuel system..
few hrs work. Finding 2stroke starting fluid may take the most of your time. And you may not need it. Good luck

Hi Keith, thankyou for the feedback, motor starts easy no problem, its only when I put in gear and it starts to load up that it starts missing, from what I can gather there are 3 filters under the cowl ive replaced the first and considering whether I need to replace the medium pressure filter on top of motor and VST filter which look to be straightforward enough based on utube videos, boat did sit for a couple weeks b4 got a chance to try out new filter.

[Keithbaja]

HPDI's have I think off the top of my like 13 filters. I suggest you look up "phase Sebaration" If your running ethanol fuel, you might a large blob of water in your tank. (Nasty on 2 strokes) any time I find water in a system I go thru it completely and recommend STAR TRON fuel additive. Do have YDS ? Which is WAY over rated for diagnostics. It'd hard to find a good, experienced tech anymore..were are slowing down with age and retirement. In a short few years its gonna be a MAJOR CRISES. PS. Get a new VST seal to seal top to bottom. Trust me. You're be glad u got a new one. "gaskacinch" makes a easy job. If you don't have JIS screwdrivers take Phillips and give a good whack on the screwhead and that helps alot.

[99yam40]

pick up tubes in tanks are close to the bottom of the tank, but are not right on the bottom.
So water in the tank rolls around on the bottom of tank until it gets bounced around at just the right time to get sucked up and sent on to the motor.

you have not said what kind of fuel you are using, is it non ethanol fuel or not?

high pressure pump has screens as do the injectors themselves.

have you drained the vst to see if any water came out?

Something else to think about.
HPDI motors do not fire all cylinders while in neutral,
if the motor thinks the motor is still in neutral when it is in gear you will feel those cylinders not firing

[johnnyrob]

HPDI's have I think off the top of my like 13 filters. I suggest you look up "phase Sebaration" If your running ethanol fuel, you might a large blob of water in your tank. (Nasty on 2 strokes) any time I find water in a system I go thru it completely and recommend STAR TRON fuel additive. Do have YDS ? Which is WAY over rated for diagnostics. It'd hard to find a good, experienced tech anymore..were are slowing down with age and retirement. In a short few years its gonna be a MAJOR CRISES. PS. Get a new VST seal to seal top to bottom. Trust me. You're be glad u got a new one. "gaskacinch" makes a easy job. If you don't have JIS screwdrivers take Phillips and give a good whack on the screwhead and that helps alot.

Running 91octane fuel, don't think its ethanol, oops way off on the filters, so ive drained the vst tank and its clean and clear so not so sure now whether to replace filter in there now?

[johnnyrob]

pick up tubes in tanks are close to the bottom of the tank, but are not right on the bottom.
So water in the tank rolls around on the bottom of tank until it gets bounced around at just the right time to get sucked up and sent on to the motor.

you have not said what kind of fuel you are using, is it non ethanol fuel or not?

high pressure pump has screens as do the injectors themselves.

have you drained the vst to see if any water came out?

Something else to think about.
HPDI motors do not fire all cylinders while in neutral,
if the motor thinks the motor is still in neutral when it is in gear you will feel those cylinders not firing

running 91 octane, not ethanol, drained vst clean and clear, so reluctant to replace filter here, going to do another sea test to confirm rev info

[Keithbaja]

The vst filter yammy says u can't clean. I have back washed with break clean a few times, but the micron size is so small I can understand why they recommend to replace

[johnnyrob]

So finally got boat back on water for trial after changing the clear bowl filter (which was black in the meshes compared to a new one) at the motor and ran fine for 10 minutes under load, then started missing again, checked and found more water in bowl /water separator on boat filter..drained this and checked motor clear bowl and drained vst tank, which were fine, but still missing under a little or lot of load and sometimes was dying completely, so seemed to be lack of fuel supply rather than the odd cylinder miss So took home drained fuel tank which had 120lts of a potential 240, this time but found very little water, maybe 1/4 of a cup, and some black residual impurities that although they had a grainy texture, readily broke down when rubbed between your fingers, so going to order the metal filter above the vst tank and see whether this helps.
Did have another query, also and wondering whether this is part of the problem, ive just replaced the primer bulb as it didn't seem to harden up fully when trying to prime up and I was concerned it might have been sucking air as you can hear air suction when squeezed but I think the noise is coming from is it a LP vacuum pump between the primer and the new sender unit?
Thanks for your help guys, Id be lost without it

[robert graham]

My brother in law got water in his fuel tank on his fuel injected 115 Yamaha and it was an ordeal getting the system clean and running again with several fouled fuel injectors( cleaned and re-installed)…. Injectors don’t like water….

[Keithbaja]

Jonnyrob. I am not way off about how many filters that motor has. I'm a Master Tech and have no reason to lie or bs you. You are making yourself appear foolish. They are SS Screen filters. the VST tank is a plastic type. G'day

[johnnyrob]

Thanks keith, I appreciate the feedback and your ideas, to clarify my thinking once I changed the small filter in the clear bowl at the motor, and took for retest, it ran without a problem with a lot of stops and starts and checking of the main filter and water separator for water etc with no problems, so thought had it sorted.
until the last time I didnt trim the motor when we took off and the attitude of the boat was bow high which I assume allowed the last residuals of water in the fuel tank to get sucked up as it then started missing again so I stop and check main filter and sure enough the water separator bowl was full of water this time,

so back to square 1, so as Ive said I drained the main fuel tank and got more impurities out of it than water, Ive drained the vst tank 3 times and havent seen any water leading up to the vst tank , and the fact that the motor ran ok initially after I changed that dirty filter in the clear bowl at the motor surely says I was on the right track doesnt it?
since I havent found any water at the motor makes me wonder whether its those black impurities that would of got sucked up with the water that could be blocking up the filters and impeding the flow,

so I am going to change the larger round metal casing filter or is this the screen filter you were talking about Keith? which supplys the vst tank, as from my understanding this is a higher micron than the previous one and could be blocked up more with some of what I got out of the petrol tank, that filter alone is $230 and I have to order it.

If this doesnt add up feel free to comment, I had a brain injury so not as sharp as I used to be! or is it an over 60s problem

[TownsendsFJR1300]

so back to square 1, so as Ive said I drained the main fuel tank and got more impurities out of it than water, Ive drained the vst tank 3 times and havent seen any water leading up to the vst tank , and the fact that the motor ran ok initially after I changed that dirty filter in the clear bowl at the motor surely says I was on the right track doesnt it?
since I havent found any water at the motor makes me wonder whether its those black impurities that would of got sucked up with the water that could be blocking up the filters and impeding the flow,

I've had black spec's (larger than a spec actually) develop and get caught up in the under cowl filter.

Further digging it was found to the the marine fuel line from the transom filter to the engine line breaking down and the internals coming apart.
The engine filter caught it all (found it just doing maintenance, no running issues, so it was caught early).

I had replaced that line some years ago which WAS Mercury Brand Marine grade fuel line...


So you may want to check the innards of the line for disintegration..