Striper Talk Striped Bass Fishing, Surfcasting, Boating - View Single Post

Mr. Sandman · 07-20-2003, 12:56 PM

Have you got the right prop? It looks slightly under pitched to me. 4500 seems too fast for 20 Knots. 6100rpm WOT also sounds high. I don't know the numbers for 4 strokes but most big 2-strokes are in the 4500--5500 WOT. I would *think* that 4 strokes are even lower...I could be wrong for these new 4stroke outboards but it seems odd to me that they would be higher then a 2 stroke. (Generally a 4 strokes peak performance is produced at a lower rpm (producing higher torque) ...when compared to two strokes....ie: motor cycle vs auto)

I would check this out with the dealer.

(A over-reving engine could cause bearings to over heat...burning oil....just a though.)

good luck

ps.

I just read thru my service manual for my 2 stroke and it says that there is software in the computer to prevent rpms > 6100 . It starts cutting out injectors to prevent exteneded running beyond this rpm.

07-20-2003, 12:56 PM	#3
Mr. Sandman Registered User iTrader: (0) Join Date: Sep 2001 Posts: 7,649	Have you got the right prop? It looks slightly under pitched to me. 4500 seems too fast for 20 Knots. 6100rpm WOT also sounds high. I don't know the numbers for 4 strokes but most big 2-strokes are in the 4500--5500 WOT. I would think that 4 strokes are even lower...I could be wrong for these new 4stroke outboards but it seems odd to me that they would be higher then a 2 stroke. (Generally a 4 strokes peak performance is produced at a lower rpm (producing higher torque) ...when compared to two strokes....ie: motor cycle vs auto) I would check this out with the dealer. (A over-reving engine could cause bearings to over heat...burning oil....just a though.) good luck ps. I just read thru my service manual for my 2 stroke and it says that there is software in the computer to prevent rpms > 6100 . It starts cutting out injectors to prevent exteneded running beyond this rpm. Last edited by Mr. Sandman; 07-21-2003 at 07:31 AM..