2 different problems at the same time with both Yamaha HPDI 200 HP? Can anyone help? - The Hull Truth

shoemaker · 09-14-2008, 06:58 PM

My buddy has two problems with each one of his Yamaha 2001 200hp HPDI's? One engine runs good until it gets to 33rpm or over, after 5 min of running at this speed the engine drops RPM's down to 22 to 26RPM. He changed the VST Filter (it was dirty) and the fuel pumps, and then it ran better but still drops RPMs after running well for a few min. Also his other engine will run great and then it just shuts off and comes back on? It stalls at high RPM over 33RPM and now will shut off on Low RPM, It surges then comes back on? The 3 bars will flash, then come on. Its strange as hes running at a high speed then the surge where the engine shuts off and then it comes back on??? Can anyone help us? Its really driving us nuts. Thanks for any help on what to look for. The engines run good other wise and have good compression and about 700 hours on them.

A1 Outboard · 09-15-2008, 07:11 AM

Wow, he has some winners there. Without seeing and actually testing the motors I can only offer educated guesses, but hey, you get what you pay for, right?

The motor that cuts out and displays 3 bars on the gauge probably has a loose or corroded battery connection somewhere making an intermittent circuit. If there are wing nuts on the batteries, change them out for stainless steel nuts and lockwashers for a secure connection. Clean all the terminals and battery posts until they shine.

The other motor sounds like a fuel delivery problem. Most mechanics never change the metal mid-pressure filter located in the line just above the vapor separator tank (VST) that connects to the belt driven high-pressure pump. It can collapse internally and either restrict the flow to the pump or can allow debris to ruin the pump. Get both filters (expensive) changed right away.

The Yamaha manuals and technical guides show how to test for fuel restrictions and air bubbles in the boat's fuel system, and how to test for fuel pressures at the diaghragm pumps and the electric mid-range fuel pump. A laptop and the YDS is needed to monitor the high pressure readings.

shoemaker · 09-15-2008, 10:55 AM

Quote:

A1 Outboard - 9/15/2008 6:11 AM

Wow, he has some winners there. Without seeing and actually testing the motors I can only offer educated guesses, but hey, you get what you pay for, right?

The motor that cuts out and displays 3 bars on the gauge probably has a loose or corroded battery connection somewhere making an intermittent circuit. If there are wing nuts on the batteries, change them out for stainless steel nuts and lockwashers for a secure connection. Clean all the terminals and battery posts until they shine.

The other motor sounds like a fuel delivery problem. Most mechanics never change the metal mid-pressure filter located in the line just above the vapor separator tank (VST) that connects to the belt driven high-pressure pump. It can collapse internally and either restrict the flow to the pump or can allow debris to ruin the pump. Get both filters (expensive) changed right away.

The Yamaha manuals and technical guides show how to test for fuel restrictions and air bubbles in the boat's fuel system, and how to test for fuel pressures at the diaghragm pumps and the electric mid-range fuel pump. A laptop and the YDS is needed to monitor the high pressure readings.

wow, A1 thats the only filter he did not change (the one above the VST filter. He did change the VST filter and it was dirty but not the one above it. Maybe thats the problem? I will tell him to change it. And let you know. Also he did change a bad ground cable and took off the wing nuts and replaced them with the stainless steel nuts and its helped, but he still has a cut off and back on problem.. Maybe its another cable? What about the key switch? Could it be that? Thanks again for you great help A1!!!

A1 Outboard · 09-15-2008, 11:04 AM

Yep, it could be a key switch, a boat wiring harness connector, any problems along the yellow wires, etc. Problems like that are sometimes hard to pin down as they take time to find and they only act up intermittently.

Every ground wire on the motor should be removed and cleaned as well as the fastening area of the block.

I wish y'all luck.

brianm333 · 09-16-2008, 09:10 AM

I have the same problem with one of my 200 hpdi's. Motor loses rpm and the 3 bars flash on the bottom. Somedays its good and other days it happens alot. Checked attery terminals and connectors, even swapped ignition switches did not help. Took off all small grounds going to the block, cleaned them, even though they were not corroded, and retightened. It hasnt happened the last 3 times out but not convinced its fixed. Only time will tell.

shoemaker · 09-16-2008, 05:44 PM

Thanks Guys, He change the filter above the VST tank LIKE YOU TOLD US TO DO and it was in fact bad, put new one on and the boat now gets more RPMs and will run well until he gets over 40- RPMs then it cuts out and down to 28 to 36. ? Could it be that the Injectors need to be cleaned? Anything to check? It seems to run well up to 38 RPM.? The other engine runs fine until we go over 33RPM then it blows the fuse on the engine, it did it twice and we checked all battery Cabels and ground. We swapped ignition switches and ran her and the same engine still blew the engine fuse and stopped.? So its NOT the KEY SWITCH Ignition. What do you think it could be? THANKS A1 FOR YOUR HELP AND THAT INFO ABOUT THAT FILTER, the Mid- Pressure Filter was Collapsed just like you said.

A1 Outboard · 09-16-2008, 09:03 PM

The collapsed filter may have damaged the high pressure belt driven pump. You will need to monitor the pressure using a laptop and the YDS.

If it is the fuel pump fuse that blows, then there may be a fuel problem inside the boat, so all the fuel vacuum, bubble, and pressure tests must be performed and if they check OK, then that super expensive electric pump may need replacing.

shoemaker · 09-16-2008, 10:22 PM

Quote:

A1 Outboard - 9/16/2008 8:03 PM

The collapsed filter may have damaged the high pressure belt driven pump. You will need to monitor the pressure using a laptop and the YDS.

If it is the fuel pump fuse that blows, then there may be a fuel problem inside the boat, so all the fuel vacuum, bubble, and pressure tests must be performed and if they check OK, then that super expensive electric pump may need replacing.

A1, The engine that is blowing the fuse is not the engine thats losing the RPM at 40 Plus RPM and that had the collaped Mid Pressure Filter. The engine thats blowing the Fuse is the engine that runs very well at any RPM, It just shuts off and comes back on at High or Low RPM when Underway, and is now blowing a fuse at a RPM over 30 Rpms. HELP!

brianm333 · 09-17-2008, 06:34 AM

Does the motor shut off completely after the fuse blows?

shoemaker · 09-17-2008, 08:24 AM

Quote:

brianm333 - 9/17/2008 5:34 AM

Does the motor shut off completely after the fuse blows?

YES. he will kick her up to 36 RPM and then bamm, fuse blows and engine shuts down. Sometimes before the fuse blows, it will surge and go off and then came back on at high speed for a few times then the fuse blows and the engine shuts right down. When it does come back on I see the 3 black bars flashing. Once It blows the fuse on the engine, it always shuts down.

A1 Outboard · 09-17-2008, 05:09 PM

The nice thing with twin engines is that you have an unlimited parts source.

The mechanic has to determine which fuse blew and what components are protected by that fuse. Let the swapping begin! The wiring harness first has to be minutely inspected for chafing, rubbing, or nicked wires.