Phily600

I know I know there are so many of these threads already, but i think i have read all of em and tried most of the fixes with no success. Here is the details below. If anyone could help or give me some suggestions, it would be much appreciated. I took this to a really good yamaha mechanic and he cant seem to give me any direction with the software either.

2003 LZ200TXRB
21' Triton 205 DC Walleye boat
21P mercury high five prop
Stage 3 HPDI kit from Hydrotec Marine

Engine is bogging at take off and hesitating to get on plane. This boat used to jump up onto plane instantly. now bogging and taking 20 seconds to get on plane. At take off only getting 3500-4000 RPMS. Also rough idle. 85-90% power at WOT 5000RPM max. I used to get 55+ MPH @ 5800-6000 RPM
-Fuel lines replaced from tank to motor
-Primer bulb replaced.
-Anti syphon valve replaced
-Mystery filters changed
-VST cleaned and filter changed
-inline filter changed
-strainer filter changed
-Ignition coils changed
-Sparkplugs change multiple times - Top two seem to be fowling out sometimes on cylinder 1 &2. Checked spark with inductive timing gun. All six firing.
-All plug boots are within spec ohms
-Neutral safety switch is fully functional. checked with timing light and ohmmeter. Neutral safety switch will be replaced (just in case of intermittent issues)
-Fuel pressure at VST approx 50 and high pressure 700+
-LP pressure fuel pumps will be changed this week.

The possible problem items i can come up with are:
-the lp fuel pumps did not get new gaskets the last i checked them. Ordered both new and will be changing this week with the pumps.
-the oring on the strainer could be letting air in. Ordered new and will be changing this week.
-The stator is getting weak and not giving strong enough spark. I dont know how to test this.
-Is there timing on these motors? Could it be off?
-Could the ECM or ignition controller be bad?
-I heard the pressure regulator in the vst will sometimes go bad as well.

Any help will be much appreciated.

m9000

You have addressed most of the usual suspects. Have you tried running from a small external tank? You might have a partially obstructed fuel pick up or vent in the main tank.

noelm

You need to confirm the fault, spark or fuel, not both, jumping all over the place will just cost time, money and confusion.

roony

On my 04 z200 I did have similar symptoms.. But this also gave intermittent ignition fault (used yds while driving). After a long period with fault finding, it ended up to be the plug from the stator beeing hefty corroded/oxidated.

I took the plug apart, pins out etc. Filed and cleaned. And problem solved..
ps! I also went through the lot,, vst, mystery filters, fuel pumps and so on..

m9000

Good find. What motivated you to look at that specific part? There are several HPDI problem posts here now and short of looking for spark plugs firing, few are looking in the electrical side for the source of the problem.

Phily600

Was this the plug with the 7 pins in it? I heard i can do a resistance on each pin to ground and it will tell me if i have a weak stator or a bad coil on the stator as well.

roony

I had been checking out about all i could think of that could affect ignition issues, and all of that checked out fine. I also happened to have (at that point) a second 200 hpdi that was fine. So X-checked coils, ecu's and so on. I was up to swap the stator's, and discovered the dodgy plug when disconnected it. So in way a co-incidence.

roony

Yes it was. And you are correct that you can check the resistance in the coils, and verify they are within desired values.

reelintheyears

Make sure there are no kinks in the fuel line. Similar problem on a 150HPDI. I found a sharp bend in the fuel line where it entered the rigging tube restricting the fuel supply. Fixed it with a zip tie.

Phily600

Update 4/27/2020
-Ran the same off of external tank.
-LP fuel pumps and gaskets replaced (made no difference)
-Strainer filter found upside down. made no difference after flipping. although I did see the fuel level slowly dip in the strainer when idling and even more when running the boat slowly in reverse at the dock. Does this mean i have an air leak in the lines somewhere? Primer Bulb was not staying hard. can i do a test of the fuel lines to see if there is an issue on the motor?
-Inline fuel filer replaced. Can the high pressure fitting on the fuel filter/line possible go bad and breath air?
-Stator tested OK along with all plug wires/boots and coils. Electrical system seems fine.
-Replaced plugs again today with cleaned plugs. When pulled Top two plugs were wet and seemed fowled.
-at take off 3500-4000 RPM both drive and passenger on the boat had to get onto the bow to get on plane. once planed out Max RPM 5000 @ 43MPH.
-Motor seemed to be pulsating at 2000-2500RPM while resetting drift for fishing.
-Can the reeds get stuck closed and not allow air flow to the motor? Could this cause plug fowling issues? It seems as if it wants to get into the power band but missing it by 500-700 rpms at takeoff.
-Could there be an adjustment to the throttle or oil pump that is pushing too much fuel/oil and is Flooding/Fowling the plugs. running real rich from the look of the plugs.

Aliboy

Haven't read that you have done a compression check yet? Rough idle, wet plugs, low wot, could all point to low compression on a pot or two.

fishguts

Have the injectors been cleaned and flow checked. Brucato FIS is where I sent mine. Was extremely happy with the results.

m9000

When you ran on the external tank, was the run on a hose on land or a full on the water test?

You added a Stage 3 HPDI kit from Hydrotec Marine. Have you called them to give input? How long ago was the kit added?

I second the compression test suggestion

Bayfly

Although I have a lot of auto and marine mechanical experience I'm not sure just how I would definitively determine if the problems the OP is having is spark or fuel if it were my 200 HPDI? Any suggestions from those familiar with the complexities of the engine would be appreciated.
Wow! I just went to Hydrotec Marine's website after I re-read the thread and noticed their stage 3 kit had been added, so my question is: did the OP add the kit himself or did Hydrotec's professional mechanics add the kit. The difference is Hydrotec Marine completely goes through all aspects of the engine, fuel and electrical when they add the kit. Also, it would help to know why the kit was added to the engine in the first place, maybe a blown engine?

Phily600

Compression is OK. I do have one cylinder that is lower but all over 100.
-External tank was ran on the water.
-Stage 3 kit was installed by Hydrotek on a new power head from Hydrotek and all injectors we cleaned when installation was complete. Power head was installed by a Yamaha mechanic in 2018. Boat ran fine for 6 months.

KBH

What do you get for $3,117 performance wise?

Phins360

Having twin 2004 300 HPDI on our work boat I've seen just about anything these HPDIs can throw at you.
Have you checked your TPS yet? Sounds to me like you are not getting all the cylinders firing. A faulty TPS will tell your engine it is at "idle" and only allow a couple cylinders to "work". If the TPS checks out ok I'd scope the engine. If you pushed the motor in present state you might have holed a cylinder, or more. I'd check that next. You hit all the other usual suspects.
Too bad rodbender isn't here anymore, he knew these motors inside and out.