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HPDI Vmax issue


mulligan

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I have a 05' VZ250.  Today while I was out the motor was real sluggish out of the hole and could only spin up to about 4700rpm.   I did notice it seemed a bit slow leaving the dock but not enough to think much about it but on the last little run back to the doc, is when it became real noticeable. I have not looked into it yet but was wondering if any of you guys might have a starting point.?  ALL filter were changed about 20 hours ago along with cleaning the injectors. I did do a compression check when I got home thinking it might be the worst but compression was 118-120 across the board.  I will add that it also seems like it has used a lot of oil on this trip. Thanks

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Injector drivers maybe, mine was doing something similar and all my mechanic did was swap them out with each other, for whatever reason it fixed it, he's done it on several vmax's now. Having said that, also check anti-siphon and primer bulb and low pressure fuel pumps.

 

 

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Thanks,  I will look into the drivers.  The primer bulb never went soft and is fairly new.  I will check my log but I think the low pressure pumps were replaced about 50 hours ago.  I think I might have to bite the bullet and take it in to have it plugged into the computer and have the hp pump tested.

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Mine did something similar last fall and after replacing/cleaning several filters and the low pressure pumps it ended up that it was the spark plugs.  They looked fine and were a year old or less with no noticeable cracks or discoloration.  I had checked them prior, and did a compression check, and the plugs looked good but the wife said I should get new ones and that fixed it (I will forever be reminded of this).

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All the mystery filters were changed with the rest of them,  I am very anal about the filters on this motor.  The plugs are not that old but I still have the last set I took out that I can throw in to test out, hopefully that could be it and Nauti's wife will have more to remind him of if it is it and she reads this.

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If you know someone with a spark board borrow it and check spark on all coils at the same time.  Much easier to see when they all fire in order.  

Spark plugs is a good start as well. HPDI's like new OEM plugs.  I do plugs on HPDI's every season or every 100hours whichever comes first. 

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I had a few minutes after work today to take a better look.  I replace the plugs with new ones and checked the vst filter.  I also checked the pressure on the vst and checked to make sure all plugs were firing. Everything checked out fine but still had a sputter/ miss when giving it throttle in gear, runs fine in neutral.

I will hopefully be meeting with a tech later this week to run the boat at the lake and hook it up to the computer.

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12 hours ago, mulligan said:

I had a few minutes after work today to take a better look.  I replace the plugs with new ones and checked the vst filter.  I also checked the pressure on the vst and checked to make sure all plugs were firing. Everything checked out fine but still had a sputter/ miss when giving it throttle in gear, runs fine in neutral.

I will hopefully be meeting with a tech later this week to run the boat at the lake and hook it up to the computer.

On the HPDI when in neutral and even when rev'd in neutral not all cylinders fire, correct? So if it seems to run fine in neutral, and not in gear that may help you narrow down your problem to one or both the cylinders that don't fire in neutral. Just a thought

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This may sound stupid but have you checked the output of your rectifier?  I had a similar problem where the motor was running on battery voltage only and would idle but ran lousy when revved up.  My problem was caused by a plugged up pee tube and water was not flowing through the water jacket mounted on the back of the rectifier therefore frying it.

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Correct.  I think it was 2 and 5 that did not fire while in neutral.  All cylinders were firing when in gear but it was hard to tell the strength of the spark.  I have my fingers crossed it is some silly sensor or the like and not anything with the HP pump. 

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2 minutes ago, imsnookyrd said:

This may sound stupid but have you checked the output of your rectifier?  I had a similar problem where the motor was running on battery voltage only and would idle but ran lousy when revved up.  My problem was caused by a plugged up pee tube and water was not flowing through the water jacket mounted on the back of the rectifier therefore frying it.

No but I will now, thanks.

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On 5/8/2017 at 7:36 AM, mulligan said:

Thanks,  I will look into the drivers.  The primer bulb never went soft and is fairly new.  I will check my log but I think the low pressure pumps were replaced about 50 hours ago.  I think I might have to bite the bullet and take it in to have it plugged into the computer and have the hp pump tested.

I don't know anything about this guy, just saw it skimming CL.

https://tampa.craigslist.org/hdo/bpd/6106602069.html

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Mulligan, you may want to think about calling Curtis or Paul at Family Boating and let Curtis check it out . Paul has always been very fair with me and Curtis has been working on Yamahas for many years . Joe Raimondo

 

 

 

 

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Thanks again guy.

11 hours ago, dabear said:

you may want to think about calling Curtis or Paul at Family Boating and let Curtis check it out .

I spoke with a mechanic the other day to try to set something up this week if that does not pan out FBC will be getting a call.

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Hope that you find it soon and you don't have to drop it off. I have only taken one of my boats or cars to a dealer one time in my life and it turned out that with my problem a repower was the best option for me. Good luck Mulligan I hope that your baby is up and going soon . Joe R 

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1 hour ago, dabear said:

I have only taken one of my boats or cars to a dealer one time in my life and it turned out that with my problem a repower was the best option for me

 The last time I had a boat in the shop the motor was done and I sold the boat. My odds of doing it two times in a row is low, I hope.  As long as those high dollar, high pressure fuel pumps are working I think I will be ok.

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22 hours ago, mulligan said:

 The last time I had a boat in the shop the motor was done and I sold the boat. My odds of doing it two times in a row is low, I hope.  As long as those high dollar, high pressure fuel pumps are working I think I will be ok.

Remember you sold that boat to me and I rebuilt that motor. It's still running strong. Keep the faith.

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The fun continues.  I spoke with a guy last Monday about the motor issues.  He told me to try new plugs then give him a call back and if it was not the plugs he could look at it Wednesday/Thursday.  I called him back on Tuesday after trying new plugs, plugs did not help.  He told me he was still working on another project and would not be able to see me until Friday, Monday the latest.  Needless to say I did not hear from him on Monday even after I tried to contact him Monday afternoon.  I did get a return call today but the boat had already been dropped of to the folks at FBC.  So now the boat is in line to get worked on.  Sadly for me but good for the guys at FBC the had a great boat show and sold a bunch of boat they have to prep for new owners.

Just to add salt to the wound, I went to hook the boat up a 4 this morning and found a nail in the trailer tire.

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