Notices
Like Tree7Likes

2004 Yamaha 300 HPDI Poor Idle

Old 02-28-2019, 10:03 AM
  #1  
Member
Thread Starter
 
Join Date: Feb 2014
Posts: 35
Default 2004 Yamaha 300 HPDI Poor Idle

I have a 300 HPDI that won't idle smooth. The RPM jump between 700, 500, 600, 500, 400, stall. Same issue on the hose or in the water. Racor, water separator filter under cooling, BUT filter, medium pressure filrer( metal filter, injector filters(6), high pressure pump filters (4), all replaced. Fuel lines replaced and tank pickup checked and cleaned. Fresh fuel in tank, link and sync and TPS done per service manual. L/P pumps replaced and new gaskets. Coils and plug boots checked per service manual. Injector ohm check per service manual . High pressure pump 980 psi-990 psi at idle. VST pressure 53 psi. It does the same in gear and out of gear. Compression 135-140 across the board. YDS shows no fault codes. Any suggestions? Besides replacing motor.
captdwayne is offline  
Old 02-28-2019, 01:19 PM
  #2  
Senior Member
 
Join Date: May 2011
Location: Charleston, SC
Posts: 359
Default

Have you checked the 02 sensor? (assuming the 300 has one) pull the sensor cover and back out the sensor to get to the feeder tube. Mine was packed full with hard carbon deposits. Cleaned it out and soaked in seafoam along with sensor and the motor has idled beautifully ever since. my motor is a 200 HPDI however so I cant say for sure if the 300 has an 02 sensor.
Capt.Bryan K is offline  
Old 02-28-2019, 02:36 PM
  #3  
Senior Member
 
Join Date: Feb 2005
Location: Canaveral, Florida
Posts: 1,613
Default

Does it continue to idle poorly once it is warmed up? I usually crank mine up and put them in gear so all cylinders are firing for a minute or so. Generally they will idle fine the rest of the day after doing this, otherwise they will cough and stall out first thing.
truculenity is offline  
Old 02-28-2019, 02:41 PM
  #4  
Member
Thread Starter
 
Join Date: Feb 2014
Posts: 35
Default

The 300 HPDI doesn't have a O2 sensor . Thanks for the reply.

It get a little better once it warms up. But, it still surges.
captdwayne is offline  
Old 02-28-2019, 03:00 PM
  #5  
Junior Member
 
Join Date: Feb 2019
Posts: 7
Default

I had three different powerheads on mine it was the worst motor I ever had. Consider yourself lucky you haven't blown one. The 250 and 300 04 and 03 were a nightmare to Yamaha, the number 2 and 4 cylinders were the culprits. Check with a good Yam mechanic they might be able to help you.
Tallica25 is offline  
Old 02-28-2019, 03:50 PM
  #6  
Member
Thread Starter
 
Join Date: Feb 2014
Posts: 35
Default

Thanks for the info.
captdwayne is offline  
Old 02-28-2019, 03:50 PM
  #7  
Admirals Club Admiral's Club Member
 
Join Date: Jan 2016
Location: California
Posts: 321
Default

Did you change the fuel bowl filter? If so, is it seated in properly?
SeaBassHWD is offline  
Old 02-28-2019, 03:52 PM
  #8  
Member
Thread Starter
 
Join Date: Feb 2014
Posts: 35
Default

Replaced the fuel bowl filter and o-ring. Did a vacuum test and no leaks. Thanks for the suggestion .
captdwayne is offline  
Old 02-28-2019, 03:57 PM
  #9  
Admirals Club Admiral's Club Member
 
Join Date: Jul 2009
Location: LODI, MS
Posts: 648
Default

bowl filter is plastic and swells making it difficult to reinstall. must be dried out for a day or so before proper fit. I keep a spare.
nadornati likes this.
LODI QUACKER is offline  
Old 02-28-2019, 04:09 PM
  #10  
Admirals Club Admiral's Club Member
 
Join Date: Jan 2016
Location: California
Posts: 321
Default

I had the same issues and it turns out my fuel bowl swelled up. After putting a new one, it idles fine now. Can you take a pic of yours and post it?
jbg108 likes this.
SeaBassHWD is offline  
Old 02-28-2019, 04:21 PM
  #11  
Member
Thread Starter
 
Join Date: Feb 2014
Posts: 35
Default

I'll get a pic tomorrow and post.
captdwayne is offline  
Old 02-28-2019, 05:42 PM
  #12  
Admirals ClubCaptains Club MemberPLEDGER Admiral's Club Member
THT sponsor
 
Join Date: Aug 2004
Location: cape cod
Posts: 8,746
Default

First pump the fuel line bulb and watch for gas leaking from the on engine plastic fuel filter canister. An air leak from that will cause your problem. How does it run at speed? Are you getting full power and wot rpms?

My 300 idled rough and made a slick and it turned out to be bad low pressure pumps.
jbg108 is online now  
Old 03-01-2019, 02:07 PM
  #13  
Member
Thread Starter
 
Join Date: Feb 2014
Posts: 35
Default

No fuel leaking from pumps or fuel bowl when priming the bulb. I was able to run up to 5500 RPM with no problem. I double checked the L/P pumps and gaskets. All good. It runs rough/surging at low speed and in gear and surging at idle in and out of gear.
I'm not able to post pics yet. Maybe tomorrow night.
captdwayne is offline  
Old 03-02-2019, 09:30 AM
  #14  
Member
Thread Starter
 
Join Date: Feb 2014
Posts: 35
Default

Rechecked the link and sync and all is good. Rechecked the fuel pressure and all is good. Recheck Compression and plugs. All is good. Still.poor idle.
captdwayne is offline  
Old 03-02-2019, 10:08 AM
  #15  
Junior Member
 
Join Date: Dec 2017
Location: WS NC
Posts: 27
Default

I have a 2004 300 HPDI on my Kencraft 235. It's been a perfect match for my boat and an excellent motor. Pushing 1800 hours on engine and boat. I would suggest get your repair manual out and find the idle screw near the port side on the engine up near the front. Start your engine and attempt to increase and decrease the idle screw watching the change in RPM's. Given you have eliminated all possible leaks, low and high pressure fuel pump issues, which sounds like you did via YDS, you might just need a simple adjustment either up on down on the idle screw. Good luck.
seawitch123 is offline  
Old 03-02-2019, 12:50 PM
  #16  
Admirals Club Admiral's Club Member
 
Join Date: Nov 2008
Location: Jupiter, FL
Posts: 1,991
Default

Did you try new spark plugs? They eat plugs but ringfree really helps.
lobsdiver1 is offline  
Old 03-02-2019, 07:23 PM
  #17  
Member
Thread Starter
 
Join Date: Feb 2014
Posts: 35
Default

Idle was adjusted per service manual. .58 - .62 volts.
it has new plugs. Replaced about 1 hour ago. Has fresh fuel with ringfree and injector cleaner.

captdwayne is offline  
Old 03-04-2019, 04:27 AM
  #18  
Member
Thread Starter
 
Join Date: Feb 2014
Posts: 35
Default

Took it out yesterday and no change. Still poor idle. Runs good at high RPM.
Still unable to post pics of fuel bowl.
captdwayne is offline  
Old 03-04-2019, 06:02 AM
  #19  
Admirals Club Admiral's Club Member
 
Join Date: Jul 2010
Location: NJ
Posts: 2,224
Default

did you ever change out the mystery filters?
nadornati is offline  
Old 03-04-2019, 06:03 AM
  #20  
Admirals Club Admiral's Club Member
 
Join Date: Jul 2010
Location: NJ
Posts: 2,224
Default

pretty common issue.. i did mine a few years ago, night and day difference..

Here is a link i found on them : Mystery filters in Yamaha HPDI Motors
nadornati is offline  

Thread Tools
Search this Thread