I have twin 2003 Yamaha 150 hpdi's. Were running rich, no explanation from dealer. Then running lean. Blew one and Yamaha replaced powerhead. While sea-trialing the new head the other blew (lean again no explination). Anyone with similar problems or suggestions?
hello yes I have. and I am a dealer tech. how did they determine it was running rich or lean? yes I have seen some blow for no apperant reason. so far I cannot tell much about why. you can look at the last 15 min or so of run time and see what the o2 sensor and the high pressure pump was doing as well as ingector not firing. keep us posted as to what yamaha does. we hjave had problems with a few. did yours burn out the head gaskets? good luck and keep posting
Been running 18 months. Four different times both engines quit at the same time and plugs would be majored fouled, obvious too much oil(engines are completely independent). After cleaning plugs, would run ok. Dealer said it was due to low voltage during idling so they installed separate 3rd battery for electronics. This time when engine died plugs were brownish and looked scored. Dealer says print out says they're running lean and they don't know why. Yamaha is sending a tech to inspect when then replace 2nd head.They are replacing o2 sensors only as a precation. The only abnormal thing was on the first engine to blow never came up to temperature. Also, never had any alarms.
Sorry,Boat is ran on average every 4 to 6 weeks and I refill before leaving. I purchase at a large marina that turns over alot of fuel. Would expect fuel to spend more time in my tank than the marina's. Typical trip would use less than one-half tank. Did notice last summer that WOT was a two hundred less RPM.
hello so far yammi does not have the computer capeability to tell me if the motor was running rich or lean. you can look at the o2 sensor reading but there is a lot going on in the cyl and if the o2 sensor is wrong the computer wont know its wrong and may react to it. I fought a fouling problems on a lot of HPDI motors. most have the problem after trolling for tuna between 1200 and 1800 rpm for extended times. seems the thermostats are very touchy on the motors. if they overcool or get hug with a slight amount of trash it causes incomplete combustion and a rich condition. dont let them snow job ya. the tech rep tried it on me but I have had extensive mechanical and efi training. they will snow job ya in a heartbeat. I just had a big fight with mercruiser over the oil pressure being to high on a 340hp 7.4. ran 75 psi all the time. with a 2 piece seal its way to much. they kept trying to say it was the filter bypass. I finally told the rep to draw me a diagram by hand and show me how the bypass affected pressure. he finally conceded the pump was in fact wrong. new long block is on the way. so when they do your power heads maker sure the replace or rebuild the low pressure pumps. replave and clean the vapor seperator and filter. and above all replace that 190 dollar filter between the VST and the high pressure pump. if it clogs a tiny bit it will cause an erratic flow to the high pressure pump. with the DFI engines a slightly lean condition will cause fouling as well. but the plugs will have a dry sooty look. this summer I am going to test a fuel theory. as the fuel is being recirced from the medium pressure pump to the high pressure pump it heats the fuel quite a bit, then its returned to the VST, at low speeds there is not much fuel being used and with the hod on in the sun the vapor seperator becomes very warm. like a bath tub. there is nothing to compensate for hot fuel. I am going to test one by installing a fuel cooler in the return line. I really dont think yamaha is going to help us much especially after the warrenty exoires. I wont warrenty a rebuild on an HPDI, FICHT or optimax beyond the fact that it was assembled correctlyyammaha keeps saying there is no problem with the product. in fact they are now trying to blame the techs and the customers. my field service tech has never worked for a dealership and 2 years ago was an aircraft mnechanic in the navy. he only knows what the factory schools tell him. and its the same school for fuel systems I did last year. go figgue. anyway keep us posted on what they do. another season is almost upon us good luck and keep posting
RodBolt: You're knowledge of Yamaha OB's absolutely amazes me. You're contribution to this site deserves recognition and many thank you's. How much would it cost me to buy you and have you on call 24/7 in case my Yamaha acts weird? You could live in my basement. John
Best Day Ever,I wish I had seen your original post earlier. I'd like to add some HPDI anecdotes. 2004 Yamaha 250 HPDI bought Dec 1 blows Jan 9. Powerhead replaced late Jan. blows after 1 hour. Third powerhead installed by Yamaha tech mid Feb. Cause of both blows: Low-grade oil- although TC-W3 approved. Tech "recommends" Yamalube ONLY. Also, friend who owns 2003 HPDI 250 had over oiling until recalled and fixed. Changing my log to Close to Shore. Good luck keep posting.
When I bought my 4 stroke I was thinking about the Yamaha 2 stroke, Now I'm glad I stuck with my 4 stroke. I really feel for you guys that have spent all that money and have ended up with problems. I hope you get them fixed so you don't have to worry every time you take the boat out, good luck, Ben
(2) Yamaha 150 hpdi blown
yes I have. and I am a dealer tech. how did they determine it was running rich or lean?
. did yours burn out the head gaskets?
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