2004 yam 150 hp hpdi problem after winter

[Joral]

I have a 2004 yamaha 150hp hpdi motor. I got it last year mid season. Everything was running fine. It was professionally winterized at a yamaha dealer. I used the boat today for the first time. It started right away and sounded good. After going slow for about 5 minutes I tried to go faster and the boat will hesitate, like losing all its power for an instant and then it will go on fine. From there on, only if I gave it gas very slowly I could reach high speed and to get on plane, otherwise, when I tried to go fast right away, it will go on an off until. I don't know anything about mechanics but it felt like if the gas going to the motor was turned on and off. I also felt similar hesitations when going fast and hitting a wave. I will be only for an instant, but it feel like loosing all the power. During winterization, they change the water pump, the water/oil separator and I believe the gas filters. Thank you for your help

 

[jeffersondodson561]

Re: 2004 yam 150 hp hpdi problem after winter

Did you prime the primer bulb before you used it after winterization?

 

[Joral]

Re: 2004 yam 150 hp hpdi problem after winter

No, I did not prime the bulb. I also heard to check the kill switch. I will do both and report back. Thank you.

 

[jeffersondodson561]

Re: 2004 yam 150 hp hpdi problem after winter

The reason I ask is when doing winterization I would drain the VST but I always told the customer they needed to prime the primer bulb, also if they replaced the water seperator, most likely they did not fill the filter with gas (not needed if primer bulb is installed).

 

[Joral]

Re: 2004 yam 150 hp hpdi problem after winter

I finally was able to use the boat again yesterday after many days of rain. I did prime the bulb and checked the kill switch. The motor starts immediately every time and it runs very well when going slow. When I try to go fast, when I push the control level forward too fast to get the boat on plane it hesitate, it feels like if it wants to stop very abruptly. This goes on an off until I bring the control lever back again. If I push the control lever forward slowly, I can bring the boat on plane and run fast without any problem. I do not have any problem with small waves any more. I believe that was the kill switch being loose.

I appreciate all help.

Thank you,

 

[Joral]

Re: 2004 yam 150 hp hpdi problem after winter

Used the boat again yesterday. Took it for a long run. It goes well in the begining but the more I go, the worce it gets. I cannot push the control lever foward fast that the motors starts trying to shut off. At the end, I could only go at about 5 -10 mph. Is at the mechanic today. Only thing he said is he will start with the plugs. Checking and changing the plugs.

 

[Joral]

Re: 2004 yam 150 hp hpdi problem after winter

Just got the boat back from the mechanic. The engine has 85 hrs. Compresion in all cylinders is 110 (good). No computer codes were found. replaced filter on high pressure pump. Replace all spark. Now I have to use the boat and see how it run. They did not have time to test it.

 

[boatguy823]

Re: 2004 yam 150 hp hpdi problem after winter

you are describing a loss of fuel pressure. When were the filters last changed? The are two filters critical to high speed operation on an hpdi. that are most likely clogged. One is inside the vst tank and one on top of the vst tank. If either of these filters become dirty and clogged your engine will run like crap. Tell your mechanic to check the fuel pressure at problem rpm and then change them. depending on how long its been I would suggest you have ALL filters changed ESPECIALLY if you are using ethanol fuel.

 

[jeffersondodson561]

Re: 2004 yam 150 hp hpdi problem after winter

Check to see if the water seperator is tight/double gasketed. Check the engine fuel filter, air leak. Mechanic needs to more troubleshooting than just the spark plugs and hours...

 

[Joral]

Re: 2004 yam 150 hp hpdi problem after winter

I used the boat Saturday. It runned very well. I did not have any problems. The filter that the mechanic changed was called VST.
Thank you very much to everyone.