Yamaha 200 HPDI Problems

[Enki 4040]

I own a 2001 hpdi 150 and it might help if I told my experience The motor started great but would not go beyond 3,500 rpms what had to correct first was the filter- water separator mounted on the engine because it was faulty (letting air in) the next thing I diagnosed was a clogged screen filter behind the vst tank ( you removed the tank and the screen is there) next there's a inline filter beyond the vst tank replaced beyond the inline filter inside of the high pressure pump there are two 3 micron basket filters that were clogged and beyond that is a 3 micron filter before each injector . Forgot about replacing the low pressure pumps . These motor's are either loved or hated guys the loved them probably made sure to fill with clean non ethanol gas . It's my opinion that these motors are flawed in that they have the3- micron filters in the high pressure pumps which are difficult for the average person to access . The screen behind the vst tank isn't fun either. I had my mechanic take the high pressure basket filters out and I installed a 3 micron filter on the transom so nothing bad could ever get in . I also replaced all gas lines and only use ethanol free gas . Hope this helps

[Cregeis1]

I own a 2001 hpdi 150 and it might help if I told my experience The motor started great but would not go beyond 3,500 rpms what had to correct first was the filter- water separator mounted on the engine because it was faulty (letting air in) the next thing I diagnosed was a clogged screen filter behind the vst tank ( you removed the tank and the screen is there) next there's a inline filter beyond the vst tank replaced beyond the inline filter inside of the high pressure pump there are two 3 micron basket filters that were clogged and beyond that is a 3 micron filter before each injector . Forgot about replacing the low pressure pumps . These motor's are either loved or hated guys the loved them probably made sure to fill with clean non ethanol gas . It's my opinion that these motors are flawed in that they have the3- micron filters in the high pressure pumps which are difficult for the average person to access . The screen behind the vst tank isn't fun either. I had my mechanic take the high pressure basket filters out and I installed a 3 micron filter on the transom so nothing bad could ever get in . I also replaced all gas lines and only use ethanol free gas . Hope this helps

Thank you very much! I sent this to my daughter and told her to tell the mechanic to do exactly what you said!

[99yam40]

pulling those filters and not replacing them could cause problems, probably not a good idea.
they can catch stuff coming out of lines and pumps after the transom mounted filter

[Enki 4040]

Yes that's true i'am not advising that she remove any of the just where they are

[pstephens46]

Bump for Rodbolt

[rejesterd]

She took the boat out after work yesterday and the boat couldn't get on plane. She had the boat out just a few days before and it was fine.

To me, that's a key observation. That's different than a case of a boat sitting around for a while and then not being able to ever run right until the entire fuel system is cleaned.

I think the question is: what would cause INTERMITTENT power loss like this, where the interval is a few days? And hopefully we can assume that the mechanic who worked on it did basic tests (like confirming good compression and all that). My first suspect would be lack of venting in the fuel tank.

You said the mechanic replaced the gaskets for the low pressure fuel pumps. So I assume they were leaking. That could be due to the fuel tank not venting properly and eventually building up pressure in the fuel line going to the engine. That would blow those gaskets. When the gaskets start to leak, air is drawn into the fuel system, which would cause power loss. Leaks like that can cause inconsistent behavior, because the size of the leak changes with temperature (which generally changes over the course of a few days). Some days it might be small enough where the power loss isn't noticeable. And of course every time you fill up (which is another days/weeks-long interval), you'd be relieving the built up pressure in the tank.

I would tell her next time it happens, remove the fuel tank cap and see if she hears pressure being relieved. If so, that's a problem, and it would cause power loss like this imo.

[HecklerMV]

I own twin 2001 Yamaha 200 HPDI's in a setup that provides the option of feeding either motor (or both motors) from either of two fuel tanks, a Main tank and an Auxillary tank. When you think about it ,this combination affords many diagnostic opportunities unavailable to the single engine /single tank owner . The lessons I learned was its always the gas.
I have had two significant problems with my HPDI's in the almost 20 years and they were both fuel related. I hope this helps.

The first which sounds a lot like the problem with this boat was that it would run but when asked to run faster say above 3500 RPM with a heavy load, the port motor would struggle and balk and then limit its RPM to maybe 2400 . It happened once or twice intermittently and it was ignored. Eventually, it happened every time.

The fix was to replace the filter in the VST tank . ( It's possible that one was replaced and I thought two were replaced at the same time.) Problem went away and boat ran well with good performance with both motors and full RPM easily achieved. Problem occurred 5 or so years ago never returned with periodic replacement every few years of the VST filter along with annual replacement of the spin-ons and the engine mounted external filters on both engines.

The second problem was after a winter lay up and launch and after about a half hour of preseason testing in the open water at several RPMs and up to 5500, both died within seconds of each other. (sounds like another HPDI thread?) fortunately within about 5 yards from a dock.

They would both start, run for 2 seconds and die . This could be repeated with both motors behaving identically.. I saw that both motors were switched to be running off the Aux tank and concluded very few things can affect both motors in the exact same way and even more compelling, at the same time. . As it was, the fuel in the Aux tank was bad . Dumping the spin- on filter contents into a glass jar it became obvious the gas was the problem. its was cloudy and yellow with a good amount of water in the bottom of the jar.

I removed the on-engine filter and collected the gas that I hand pumped (by the fuel ball) into another container with the gas looking exactly the same cloudy and yellow !. I switched to the Main tank feed and repeated the operation but with normal looking gas coming form the Main tank. I replaced the filters primed it and the engine started after about 4 attempts and ran well.

I switched the other engine to the Main tank feed and replaced those filters and it too ran well after a few tries . I had the VST filters changed a little later as I suspected their filtering life had just been shortened as well.

There are probably many ways that gas can go bad and my experience says if your HPDI motors are running funny or not at all- it is the gas. Certainly it is one of the two reasons and a lot easier to chase than the spark alternative. . Even with one tank you can do what I did by changing the filters temporarily feeding the motor via a hose in to the spin on filter manifold from a gas can with fresh gas.

The motors ran well off the main tank all last season

The only problem is the 30 ? 40? gallons of fuel in the Aux tank that needs to be pumped out and taken care of.....$$$$$

[FabricGATOR]

Thank you HecklerMV, for taking the time and effort to post that.

I recently acquired a nice looking (still to mount and run) pair of 2005 200 HPDI's so I am starting to pay attention to this (new to me) system, theory of operation, and technology.
I'm told that they are good engines (smaller HPDI) as long as they are maintained properly and fed quality, clean fuel.

I read somewhere (likely here) that a member changed to 2 micron fuel filter. Will a two micron filter have the capacity to supply enough flow? If I go 2 mic, I may try to install them after the 10 micron's to prefilter... but really, am I thinking to much into this? Isn't the under cowling filter/bowl an adequate filtration system when combined with a 10 micron?

[99yam40]

I believe Rodbolt has said he does not recommend installing a 2 Micron

[FabricGATOR]

I believe Rodbolt has said he does not recommend installing a 2 Micron

Thank you for that 99yam40. I was looking at them the other day, yesterday in fact, and something just didn't seem like it was something I wanted to do.

[Cregeis1]

My daughter took her boat back to the dealer who sold it to her and they have apparently fixed it as the motor has run a couple of times since she got it back and the problem has not come back. I have attached the dealer's work order as it is a little confusing as to what they did and I do not want to misquote something. It was definitely a fuel issue and they replaced two different filters although I am not sure which ones. Anyway, the good news is that the motor is running better than ever! Thanks again everyone for your advice!

[pstephens46]

Sweet! Just in time for warm weather.