150 Honda Prop question

[shawnshawn]

I just picked up my new 21 Arima Hardtop. It has a 150 Honda 4-stroke. My question is for anyone who knows anything about props. Redline is 6000 rpm. It has a 4 blade 14.5 by 17 aluminum prop. Under WOT it revs up to about 5200. Then in order to reach 6000 rpm, I have to keep trimming motor up. It's still picking up speed as I trim. At 6000 rpm it tops out at 34.5 knots. But out of the hole it's pretty doggy. So I was curious if anyone had any suggestions for a diff. prop. Thanks for your help.

 

[snohomishbaddawg]

Re: 150 Honda Prop question

I am not to sure a new prop is the answer for your hole shot problem on that boat. I would take a look and see if some trim tabs might be a better solution. I put smart tabs on my 17 SeaRanger and it is great. Quicker on plane, plane at lower speed, and keeps the bow down in the chop to help smooth out the ride. As far as trimming up the motor the RPMs should go up along with the speed as you trim the motor up. <br />Give the guys at the arima boat owners group on msn a shot at this questions, I am certain there are many guys there that have the same motor on a 21SR and can tell you what their experience is with the different prop setups.

 

[Hawaiian]

Re: 150 Honda Prop question

Maybe you can raise your motor up. Is it mounted all the way down on the transom. Where is your AV plate in relation to the bottom of your hull? If you're maxing out at 5200 rpm then maybe you should go with a 15 or 16 pitch prop. Hole shot will improve and rpm's will increase.

 

[walleyehed]

Re: 150 Honda Prop question

If I read your post right, you CAN get 6000 R's...4-blade is usually a good hole-shot prop in the correct pitch.<br />Does your prop have ventilation holes drilled thru the hub????<br />You may want to consider mounting the engine a hole higher, maybe 2, and see what happens...Your R's will go up some, but it may improve your hole-shot.<br />Is there a trim stop on a Honda?? if so, make sure it is in the hole closest to the transom, and engine is trimmed clear down on take off...<br /><br />EDIT: I just read post again...If you are gaining 800R's just with trim, the engine needs to be raised on the transom..try it one hole at a time, and I think you will see some improvement.

 

[shawnshawn]

Re: 150 Honda Prop question

Thanks for the replys.<br /> The AV plate is about 1" above hull. The trim stop is set closest to transom. So it can trim all the way down. I do have trim tabs on boat and they help. This motor is new for 2004 so the dealer doesn't have any experience with it. The first 150 they have sold. They are going to send me a 14.5 by 15. As far as ventilation holes through hub I don't know. It exhausts through hub. Can you raise motor more than 1" above hull? I thought I read that you can have cooling problems. But I don't know that much about it. Thanks a lot for the help and suggestions.

 

[walleyehed]

Re: 150 Honda Prop question

Each hull is a little different, but I think you will be OK to raise up a hole and test..you'd have to really get the lower unit up to suck air on a transom mount.<br />If you look at the prop sideways, directly BEHIND the leading edge of each blade (FWD on the hub) there could be small holes drilled thru the hub there, about 1/4" holes, maybe a little bigger....do these holes exist on your prop???<br />These allow a small amount of exhaust to escape into the path of the blade actually causing a controlled amount of ventilation to occur, letting the engine come up to slightly higher R's for an increased hole-shot. when the boat gets to plane, or slightly after, the exhaust has too much water pressure to exit the holes and is forced out thru the hub as usuall.