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I have a 2003 150 HPDI with 40 hours on it. I use it to troll for salmon at idle (which is around 2.5-3.0 MPH at around 500 RPM on my GW 192). I feel that the motor is metering too much oil causing the excessive smoking at idle - it seems to smoke more than my 1987 carbed 70 HP did. I also fouled a plug while trolling this past weekend (you could feel the motor 'stumbling' as it missed). This is my second year with the boat - I took it to the dealership last year to have the 'smoking' checked out (I had a tuber complain that the smoke bothered her eyes - and I noticed the same when the wind blew smoke back into the boat). The dealership told me everything was fine. I recall reading issues with oil rod adjustments on HPDIs. Any info would be helpful. The smoke is a bit hard to make out but this is the best photo from this past weekend.
I'd almost bet that some adjustment, possibly the oil rod, is off. My 250 doesn't smoke at all regardless of RPM.
You can look back in the archives to about last summer and you will see a lotta threads about 250 and 300 plug fouling..........RARELY if ever were the 150's and 200's mentioned.
Bottom line......that motor is seriously over oiling and you will continue to foul plugs until it is fixed.
Scroll down to the post by Standing Room Only for a good description of oil rod adjustment.
Start with verifying proper adjustment. I'd also recommend monitoring both oil and fuel usage for a while. Once you have accurate data, calculate your fuel to oil ratio. It should be higher than 50:1.
You mentioned a fouled spark plug. Did all 6 plugs look the same? If one was worse than the others, it could indicate something wrong with one cylinder.
As mentioned above, call Yamaha customer care with your serial #. They can tell you if there are any updates available for your engine.
For reference, I have a 2005 175 HPDI, which is very similar to your 150. During the first 10 hours it would smoke a bit at startup only. The odor at trolling speed was offensive. However, there was no visible smoke. It burned about 30:1 fuel/oil. I adjusted the oil rod and changed from Yamalube to Pennzoil full synthetic simultaneously. Now I sometimes get a very small puff of oil during cold startup, but none otherwise. Although I have not formally measured, it appears to burn less oil as well.
jukowalcz - 6/21/2005 6:34 PM I have a 2003 150 HPDI with 40 hours on it. I use it to troll for salmon at idle (which is around 2.5-3.0 MPH at around 500 RPM on my GW 192). I feel that the motor is metering too much oil causing the excessive smoking at idle - it seems to smoke more than my 1987 carbed 70 HP did. I also fouled a plug while trolling this past weekend (you could feel the motor 'stumbling' as it missed). This is my second year with the boat - I took it to the dealership last year to have the 'smoking' checked out (I had a tuber complain that the smoke bothered her eyes - and I noticed the same when the wind blew smoke back into the boat). The dealership told me everything was fine. I recall reading issues with oil rod adjustments on HPDIs. Any info would be helpful. The smoke is a bit hard to make out but this is the best photo from this past weekend.
Check the oil rod adjustment per the service manual. Also what is the oil level like in the engine mounted tank? Is it above the upper line on the engine tank?
Andy
__________________ Andy Munao Our new parts site: www.simyamaha.com Yamaha Outboard Sales, Parts and Service 1-800-213-3323 parts@shipyardisland.com Click the logo to see our THT Vendor Forum
juko, ask for the diagnostic printout from the Yamaha YDS. That will rule out several possible problems like the TPS etc. The oil rod you can easily manually check without touching anything. All you need is a ruler and a quick removal of the cowling. If that is off, which is probably the case what is happening is your motor is over-oiling as the RPM's increase, which will only lead to problems at the lower RPMs. It's a fine line IMO, I'd like mine to be on the high side of spec as that increases oil input at WOT etc, but not so high that it fouls.
Check the oil rod adjustment per the service manual. Also what is the oil level like in the engine mounted tank? Is it above the upper line on the engine tank?
Andy
Thanks for all the great advice. The oil level in the under-cowl tank is right between the upper and lower tank lines. I just got around to checking the oil rod cam stop to the pin gap with the throttle handle at idle (neutral 'locked' position) and found it to be over 2.0 mm (see pic below - it's a little out of focus). I was able to adjust it to the point where it JUST touch's the stop (0 mm gap). Per the other linked thread - there seems to be confusion over what the latest specification for this gap is - I don't have the service manual - if you could confim this spec Andy I would appreciate it.
I think the oil rod is supposed to "just touch" the roll pin when the throttle valves are completely closed. This is not when the throttles are in the idle position. A good rule of thumb is to set the rod approx. the width of a thumbnail off the roll pin when at idle.
I would close that gap up to where its barely (red curly one) touching the stopper. Move the throttle back and forth and re-check.
Not sure if that is your problem because I have seen others set farther apart then that with no smoke. Give it a shot and report back. The 150's may puff out a little smoke on cold start but after that....none to very very little at all.
If this does not correct it I would take it back or to someone else because its not right.
Andy
__________________ Andy Munao Our new parts site: www.simyamaha.com Yamaha Outboard Sales, Parts and Service 1-800-213-3323 parts@shipyardisland.com Click the logo to see our THT Vendor Forum
I have the same motor, same year with approximately 270 hours. Initial puff or two of smoke at startup and bascially none after that. I am still running Yamalube oil and Ring Free but get a little bit of plug fouling, not much. At this point in time, would switching over to a synthetic oil like Pennzoil be of beneficial use to me? I am about 2/3 down on my oil tank and will make a switch if this is the best thing for this motor. Any replies are greatly appreciated. Thanks.
FYI- I bought a "dirt cheap" 2001 175 HPDI with 66 hours on it. The seller threw in the towel after our local dealer could not figure out why it kept fouling plugs every 15 minutes of operation. I bought the YDS and manual from Andy and went to work on it. Bottom line is the motor was over oiling which had clogged up the O2 sensor, as verified by the YDS O2 sensor reading. The fix was cheap and the motor now has 125 hours and she is flawless. No smoke, no fouling. My oil use calculation comes to 78-1.
2003 HPDI 150HP smokes at idle 
touching the stopper. Move the throttle back and forth and re-check.
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