TxGator Posted November 12, 2013 Posted November 12, 2013 This summer I ended up having to have a new stator, and both power packs changed on my 89 v150. Befor they failed it ran 46mph at 5600rpm. Now since the repair 40mph and 5000rpm is the max it will do, plus its a bit sluggish to get on plane. Nothing has changed as to the set up on the boat. Compression is good as is the fuel and the carbs are clean. The repair shop has not impressed me, I took it back when I noticed the power loss. They supposedly checked it back out and the only suggestion they had was the plugs. They changed them at cost which wasnt bad, but it did nothing to help. I talked with them again friday and pretty much just shrugged their shoulders. I was hoping that maybe someone on here might have experienced something similar. Thanks G Quote
Pa Angler Posted November 12, 2013 Posted November 12, 2013 Did you check your hub assembly on the prop as any excessive end play or slippage there will cause loss of mph although a completely blown hub will show and an increase of rpm's and a loss mph. Did they check for full throttle? It could be a throttle cable issue. Tight Lines Pa Angler Quote
Super User tomustang Posted November 12, 2013 Super User Posted November 12, 2013 Any smoke? Did you run a spark check, make sure all wires are plugged in? Quote
TxGator Posted November 13, 2013 Author Posted November 13, 2013 Throttle is opening fully, spark is good on all 6 cylinders. The prop seems fine, though I will look into it a bit closer. Thanks Quote
BKeith Posted November 16, 2013 Posted November 16, 2013 Changing the stator can cause a change in timing. If they did not check the timing on a dyno or with a test prop so the motor was loaded and above 5,000 rpm, it may be low. When you say the carbs are opening fully. Are you looking into the throat of the carbs and making sure all the butterflies are going perfectly parallel with the venture? Even when it was running it's best, it was over propped and should have been one pitch smaller. Now it may have some damage and killing even more of the rpm. If it was mine, I would have that motor turning close to 6,000 rpm with my normal load in it. Quote
Pa Angler Posted November 17, 2013 Posted November 17, 2013 Changing the stator can cause a change in timing. If they did not check the timing on a dyno or with a test prop so the motor was loaded and above 5,000 rpm, it may be low. When you say the carbs are opening fully. Are you looking into the throat of the carbs and making sure all the butterflies are going perfectly parallel with the venture? Even when it was running it's best, it was over propped and should have been one pitch smaller. Now it may have some damage and killing even more of the rpm. If it was mine, I would have that motor turning close to 6,000 rpm with my normal load in it. Isn't 6,000 rpm's is a little high for this motor as the specs state operating range at WOT is 4,500 to 5,500 rpm's. At 5,600 the motor was right around where it shoild be the prop pitch didn't change after the stater change so maybe the timing may be off. http://www.yamaha-motor.com/assets/service/manuals/1/LIT-18626-06-99_1411.pdf Quote
BKeith Posted November 18, 2013 Posted November 18, 2013 Well, you referenced a Yamaha manual for a Mercury motor. However, yes, I think I am about 200 over. I've been wrong before, and since I don't mess with black motors much, I may be wrong again but I though that motor was rated for 5,800 rpm. I find they run better and give much better hole shot if you let them over spin a couple hundred. Contrary to four stroke rational, it doesn't hurt the motor. Quote
Pa Angler Posted November 23, 2013 Posted November 23, 2013 OOOOOPS I did use the wrong specs my mistake. Tight Lines Pa Angler Quote
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