2004 Yamah 225 HPDI - no power under load

[Khaotic]

Can someone give me a place to look for the simple stuff before i take it to the shop for a rape on my wallet?

Boat was running fine today until the last 2 miles of my trip back to the ramp. RPMs starting dropping and picking back up until the last mile or so when the RPMS just dumped while the throttle was still wide open. Motor sounds HORRIBLE and tries to climb above 1500 but shakes very badly and dumps back to idle.
At idle - motor purrs like normal with normal idle thurst. Try and get back on plane and its rinse/repeat. Did not have enough power to boat the boat back on the trialer.

[ChrisH]

http://www.bbcboards.net/zerothread?id=449413

http://www.bbcboards.net/zerothread?id=630903

http://www.bbcboards.net/zerothread?id=66928

good luck.

[Skeeter Man]

I'd bet spark plugs are fouled or maybe even not the right ones.

I had a similar situation a few years back. Almost couldn't get it on the trailer after running great all day. Spent $350.00 on new filters and fuel diaphragms with a terrible mechanic. Turned out he had put the wrong spark plugs in it previously......
I got lucky and just happened to pull one and noticed the number didn't match the reference sticker on the motor.

Let us know what you find out.

[Khaotic]

I pulled two spark plugs and they are the correct plugs per the manual. Do these type of two-prong plugs need to have the gap set? Or is it done at the factory? They have been in there for a while -

they had a bit of gritty oil/carbon on them, but i don't think they are fouled. I can't find any good pictures of a fouled plug to compare them too. I can wipe off the plugs with a rag and they don't look bad. I'll see if i can find some pictures online - and post a picture of one of the plugs right out of the cylinder later today.

[SkeeterJohn]

when you say it sounds horrible what does that mean... any clunking noises or just rough?

Are all 6 cylinders firing? Perhaps do a compression check too. Rule out the bad news first and then drop some money on filters etc..

For the price of the plugs change them out also change the filter in the vst and the strainer filter. Remember at idle you don't need as much fuel as you do at full throttle.

[LaCajuninNC]

I can almost guarentee you it's the high pressure fuel strainer on the top of the VST tank!!. Same exact thing happened to my 05 HPDI..Don't run it anymore until you change it, you will damage the engine if you run it wide open and deprive the system of fuel..

[Khaotic]

Pretty much, as soon as I applied any throttle at all, it coughed and sputtered - there wasn't any clanking or other sounds that made me think thrown piston or lower unit (i've had a lower unit shell out before - thankfully not on this boat...) - kind of hard to describe it really - but it felt and sounded right at idle so thats what i let it do to get me home. The wind was FAR to strong for the trolling motor to be a real option that far from the ramp.

I'm trying to touch base with a local dealer to order the parts for the VST filter. Following threads on here - it shoudn't be too tough to do. I just dont want to forget something like an ORING.

[LaCajuninNC]

Before taking it to the dealer and spending that kind of money..replace this strainer then give it a shot...order it @ boats.net or a similar online store or get it from your dealer (dealer will cost you more though)
It's easy to replace, just go to the Yamaha board..
http://www.bbcboards.net/zerothread?id=319634

trying to save you a little dough..

[SkeeterJohn]

Good advice... I'd do that first as it definitely sounds like a filter than anything else.

[Neilslure]

Buddy of mine had a similar issue with his Merc EFI this weekend. His primer bulb was going flat.

[Khaotic]

I ordered the strainer, the internal VST filter and the 10micron filter in the water/fuel sep. I started with the water/fuel sep filter since it was the easiest to get to. (Ok, after changing the spark plugs)
After putting the the new filter in, double checking the o-ring for nicks/cuts, I put the bowl back on and tightened down the collar. Pumped the ball and - it leaks. Took it apart, reaccomplished the fit and install, pumped the ball and it still leaks.
Gas is seeping out from the threads. Took it apart a third time and checked the o-ring again - still good. Put it back together, get a good and tight seal with the colar and- it still leaks.

I'm pretty much stopping here for now. GOing to look into getting a new O-ring or possible swapping out the whole assembly.....

local store had a replacement O-ring. Gonna slap that in tonight


Modified by Khaotic at 2:40 PM 4/25/2011

[skeeterbit]

just thinking fuel injection pulls fuel to motor no need to pump bulb may put more pressure on threads than they were designed to hold not a pro here just thinking out loud.

[Khaotic]

I know its been - and this may already have been brought up in another thread, but...

it seems that the plastic bowl is an issue Yamaha has their eye on.

After talking with my old service reps (i've since moved out of his area) their lead tech told me that the bowl can become warped and he's had to go as far as put them in the freezer for an hour or so to get the bowl to fit properly to let the collar snug it up (talking about the fuel/water seperator & filter bowl on the port side of the motor) he also mentioned putting an excess amount of lube on the aluminum part of the fitting before trying to put the bowl in place.

Unfortuantly, none of that worked for me. I can NOT get my bowl to fit properly into the fitting. I've even replaced the O-ring.

The cost of the bowl is $130 while the whole assembly is only $20 or $30 more. So i'm thinking just replace the whole darn thing....