Lost 5 mph

[CGWright]

My motor had been running at only 5k rpm's, and due to lack of time I took it to the dealer. Mechanic spent a lot of time on it, and talking to Yammi, and I spent $235! I got it back and it runs about 5,600 rpm's WOT with 3/4 fuel & 2 people.

The prop is a 25 TXP, and the hydraulic jackplate is set where it previously ran 70 under same circumstances, and 71 - 72 by myself. (I don't know the height exactly, but it is about 3/4" under pad.)

The mechanic said it's within Yammi specs @ 5600 rpms & 66 mph. 66.2 was the best I could get on a pretty calm day, by myself with a slight chop and 75* water.

The holeshot also seems to be lacking from before all this.

Any thoughts on what I can check? I'm not used to working on an outboard, so I'm clueless on what or how.

[Texas Larry]

What did they do for the $235? That's about what mine is running. I was going to do a little more investigating to increase my rpm.

[HaulinBass]

Gross inspect their work. Check to see if it's WOT. Even the best can miss something. Did they dyno it?

[Muz]

I talked to Yamaha after I lost 500 RPM(they say my 250 should turn 6000 RPM) and the first thing they said to do(like everyone on this board said) was to change out the filters. Medium pressure filter for sure.

Mine are getting changed out in the morning. Will post the results. Also changing the filter at the bottom of the VST

[CGWright]

<table width="90%" cellspacing=0 cellpadding=0 align=center><tr><td>Quote, originally posted by Muz &raquo;</td></tr><tr><td class="quote">I talked to Yamaha after I lost 500 RPM(they say my 250 should turn 6000 RPM) and the first thing they said to do(like everyone on this board said) was to change out the filters. Medium pressure filter for sure.

Mine are getting changed out in the morning. Will post the results. Also changing the filter at the bottom of the VST


</td></tr></table>

I asked them to check the filters.....don't know whether they did or not. They probably don't like being told what to check by someone who isn't a mechanic. This morning I'm going to send the owner an email and ask him about it.

No, they didn't dyno it. The bulk of the cost was mechanic labor for running the boat, and for consulting with Yammi.

[WDBrand]

If my mechanic told me my motor was operating within spec. after I lost 5-6 mph on top end with a weaker holeshot I would change mechanics after questioning his knowledge. Your loss in power is roughly a 50 HP reduction, using the 10hp/MPH rule.

It is obvious there is a problem and I would start with the basics, such as: fuel filters and pull a couple plugs and check condition. I would also check throttle linkage to make sure full throttle is obtained. Make sure and use the hotfoot while checking the full throttle at the engine.

[CGWright]

I agree, Willie, but competent marine mechanics are hard to come by in Michigan. At least I haven't had anybody recommend a place to me, just which ones not to use.

The mechanic told me he did check the throttle linkage and hot foot.

The owner just answered my email and said he would talk to the mechanic regarding filters, etc. We'll see how this goes.

I've been extremely frustrated with this mechanic on several occasions, but they usually make things right in the end. It's just not as easy as it should be, but I guess my work ethic just isn't the same.

Now I just wait.

[CGWright]

I just talked to the lead mechanic and he said they will change those filters. Wow, is that ever pricey. $450. No, I'm not mechanically inclined anymore so it's safest to have them do it, nor can I find the time.


They said they ran the boat with the computer hooked up and did not see any fuel pressure drops.


If the filters are plugged, would they be able to read a pressure drop? Does it still make sense that it could be the VST and medium pressure filters?

[Muz]

I just test ran my boat after the filters were changed and still no change

5500 RPMs


Not sure what to check next

[rid 05 198]

I would tell him, too put down the crack pipe and back away from my boat!

[spider1]

Guys believe it or not this seems to be a common problem with the HPDI's from what I have been seeing. Now I am not a mech. or anything but I have seen a lot of this problem with no answer. All fuel pressures will be in spec. from the low to the high but the motor just seems to fall on it face at the top end. Every dealer will put it on the laptop and everything will look good and most places will tell ya that there is nothing wrong. But we know better!!!! I would never buy another HPDI and not sure if I would buy another Yamaha. Sure hope the SHO is a better motor then the HPDI!!!

I have finally had all I could take chasing this problem for 2 1/2 years now..
By the way I lost almost 10 mph...

Good luck...

[Muz]

Thanks for your input Spider

[rangerguy]

I know what you are talking about Spider. I can't get over 5200 on my 300 and I have changed props and jackplate heights and still can't get the 5500 to 5800 they recommend and I have changed everything from filters to plugs and props. Plus the water pressure sucks, have changed poppit valves and water pumps and still can't get over about 14 psi at WOT and 0 psi at idle and this motor only had 50 hours on it when all this started. 70 hours now. This will be my last Yamaha and don't get me started on the Fuel and Oil usage.

[CGWright]

UPDATE
I wrote to the owner and told him that's what I wanted VST and med pressure filters changed. They did it for $350, and I went for a test ride yesterday afternoon.

The water was too rough to prove it out well, but we did manage 5800 rpm's with two of us and a lot of boat chop. Best we saw was 65.3 gps, but it was also 90 degrees and humid plus bad water. Will have to try another time. Good news is it was revving better and had better holeshot.


We'll see when I get better condigtions.

[BasinBoy]

Well Gentlemen, I was just looking at the Yamaha Motors board hoping I could find some information to why my 225 HPDI is NOT getting any water pressure and why it has LOST about 5 - 7 mph since 2007.

The speed issue is a long story and really not all that important to me since the water pressure issue is much more serious.

In a nut shell, I recently acquired this ZX225 in mid-April from the guy who bought it from my brother in late 2007. The guy did have the mid section and lower unit changed last year and had only a few hours on the new parts when I got it. My first trip out I noticed it was a different boat which I thought was mainly due to the prop and motor height.

Well, after many adjustments and a new prop, I only improved my top end just slightly. Note: I lowered the motor so it isn’t too high. But the water pressure issue I'm having is becoming a growing concern. I had the water pump changed. I pulled the thermostats, flushed the motor w/ water, disconnected the water line from the gauge and top of the head and blew 200 psi of air thru the line, checked the gauge...just about everything I could do to solve a water pressure problem to no avail.

At idle I have 0 psi and at WOT I have about 8 psi. If I idle for a long period of time the horn will go off. Luckily it has not gone off while running at or near WOT. At idle, the pisser is just trickling compared to most HPDI’s that are shooting a steady stream of water.

-Could something that is out of alignment or even missing from when the midsection was changed be restricting the flow?
Thanks,

[BuzzB8]

You said nothing about the poppet valve, have you checked it for debris?

[BasinBoy]

<table width="90%" cellspacing=0 cellpadding=0 align=center><tr><td>Quote, originally posted by BuzzB8 &raquo;</td></tr><tr><td class="quote">You said nothing about the poppet valve, have you checked it for debris?</td></tr></table>
I read the post at the top of the Yamaha page about the poppet valve and decided to give my mechanic friend a call who happened to be at the Yamaha parts dept. I gave him the part numbers and he will change it out for me tomorrow. I wish I had time to do it myself.
Next is to figure out what really happened to that 5 mph.

Thanks!