WOT RPM'S FLUCTUATE ON ENGINE

[ChampRiderz]

AT wide open throttle i am getting a condition on my yama 225 hpdi VZ225TLR

The duplication
WOT
RPMS drop about 300 and come back and drop and come back

no water in fuel
Fuel Filter was dirty so we are checking that

WOT also only delivers me about 56oo rpms and that is low also

Jackplate is about 3"BP
Turning a 26p out of box tempest plus
198Elite Champion

May have a little too much pitch but think fuel filter may solve the issue as we dumped excess fuel into mason jar and saw some sediment.

While we are in maintenance mode are there any other popular issues that will cause this issue???

Thanks for any and all comments!

[spider1]

This motor has a lot of filters and if one is dirty then you may want to change them all to be on the safe side. I also am assuming that the one you are changing now is the one in the boat. After that their is one on side of the motor, one in the VST, one just past the VST and then the injectors them selves has a screen and there is a screen behind the fuel regulator.

Are you running ring free or seafoam?

[ChampRiderz]

Today we changed the following

Boat fuel/water separator

Engine:
External Filter F/W separator

VST Filter
The upper filter which i think some call a strainer and it is inline up top outside the fuel float assembly.

I did take the back side of the top of the fuel float assembly apart and look at that little 1/4" screen that appears to be pressed in.

The side of engine fuel filter the one that has a sensor on the bottom of it to alert you of water in fuel was NASTY! But the VST and the upper canister filter that is inline was super clean. I was actually disappointed I was looking for a red elephant to jump at me so i could say aaahhhh there is the problem but, with the exception of the outside filter it looked good.

What else would you suggest I do?




Modified by ChampRiderz at 10:19 PM 9/29/2009

[ChampRiderz]

We are running no ethanol fuel but, we just got the boat so who knows about the previous owner.

We run Ring Free

We also run marine stabil in the fuel just for giggles! not the red




Modified by ChampRiderz at 10:19 PM 9/29/2009

[spider1]

Has the motor sat up for a long time?
Have you run it yet with the new filters?

[LaCajuninNC]

I can almost bet it's the high pressure fuel filter..the silver canister filter above the VST tank..the same thing happened to mine a while back..

[ChampRiderz]

UPDATE

Took rig out today and fished Lake Seminole and got some run time on the engine.

We have replaced
VST Filter
The Silver Canister Filter up top
Verified that the litttle 1/4" screen inside the fuel float is clean
Changed Water Fuel Sep on Boat
Changed Water Fuel Sep on External Port Side of Engine.

We moved Jackplate up from 4-1/8" BP up to 3"BP to get it close


RESULTS
Boat still has same condition RPMS top out at 5600
At 5600 and WOT the r's fluctuate downward 300 rpm's and you can feel it in the seat
ABOUT ----67mph this means moving the plate did nothing. It may have a better hole shot!

I might add that today was excellent weather condition as far as humidity and clean air with high pressure. Not a cloud in the sky


Modified by ChampRiderz at 8:53 PM 10/1/2009

[ChampRiderz]

Final results posted over in the Champion Forum

http://www.bbcboards.net...25199

Take a look if you are having these problems or were one of the many that helped us find a solution!!

Thanks to all you guys for the big Help!!

[spider1]

Hey your link does not work!

[lakefolk]

http://www.bbcboards.net...age=2

here it is

what did you use and what was your decarb procedure??

[ChampRiderz]

Well the preferred way is with a ring free shock treatment and the instructions are on the label.

HOWEVER! That is not what we did. When we pulled the plugs out we saw carbon cake on the last few threads of the cylinder heads where the plugs go in. I used a pen light and saw the top of the piston and it was also cruddy.

My guess is the previous owner did not know about ethanol fuel and the effects of it. I also believe that from the looks of the plugs and pistons a no go on Ring Free as well.

So here is the can


And here is what we did:
Take plugs out
Sprayed 50% of can into all 6 cylinders, Not evenly as some pistons were near TDC
Reinsert plugs and waited 15 minutes
Put it in the water and idled around for 10 minutes

Did it again and used the rest of the can
Idled for 10 more minutes then put it on top at 3000 r's and brought it back in

Installed new plugs and made a 3-4 minute run at 4000

and then we opened her up and she screamed!

Now the contents of this can was designed for carb engines and you run the engine till it chokes down shoving this stuff in it then let it sit for up to 14 hours.

We did this procedure on the advice of a marine tech from Boyd's marine in Dothan Alabama!

USE THE OLD PLUGS TO DO THIS PROCEDURE OR YOU MAY AS WELL BUY 2 SETS!!

You never know what you may hear on a site with opinions so what we did may have been dead wrong but, the carbon is gone! Now I'm not gonna say my pistons look like they are fresh out of the machine shop with a nice billet cover but they are clean.

[Bassin Bob71]

Just my $.02 - this is why I will only run synthetic oil. I know all the discussions here about synthetic vs. conventional oil, but I have never heard of synthetic causing carbon build up like you're talking about. Everyone's got an opinion about it and believes what they want to believe.

If that HPDI was mine, I'd switch it over to Amsoil Injector HP immediately.

Glad to hear you got 'er running good

[ChampRiderz]

When the warranty runs out sir,,, that is certainly our intent

[Bassin Bob71]

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ChampRiderz &raquo;</TD></TR><TR><TD CLASS="quote">When the warranty runs out sir,,, that is certainly our intent

</TD></TR></TABLE>

$.02 more..... I switched mine over to Amsoil at 15hrs. I know this board is split 50/50 on what the right thing to do is. Here's my thinking.......I am not worried about a failure caused by not using Yamaha oil. Even if I were to have one, I think my odds are pretty good of getting an issue such as this covered under warranty. Some on this board have had warranty repairs covered while running Amsoil. I have bigger fears of computer failures, stuck injectors, or lower unit issues than I do due to oil break down or failure.

I understand the warranty wants you to run TCW-3 rated oils but some of them I wouldn't run in my weedeater. Amsoil burns super clean - much cleaner than Yamalube or any of the other non synthetic oils. I have a 5 yr warranty........I don't want to spend the first 5 years carboning up my new motor only to have to TRY to remove it later. Why not start with it clean and keep it clean.

I'm not running Amsoil just because its Amsoil.......if Yamaha made a full synthetic, I'd be all over it. OK, I'm off my soapbox now