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Author Topic:   Engine Mounting Height

D37 posted 07-23-2007 07:47 AM ET (US)
We just had a 2007 150 OptiMax put on our 190 Nantucket. The old 135 OptiMax was installed in the third hole, the 150 is installed lower in the first hole. What is the difference and how does this effect performance. Should I have them reinstall it in the third hole?
Thanks
jimh posted 07-23-2007 08:29 AM ET (US)
Boston Whaler very likely conducted a lot of testing to determine the best mounting height for the motor on your 190 NANTUCKET, and that is where they mounted the original motor. It seems rather odd that you would just discard that advice and choose a new mounting height for the replacement motor, which is more or less identical in its dimensions and gear case as the original. I am just curious, but on what basis did you or the dealer installing the motor decide that you ought to change the mounting height?
D37 posted 07-23-2007 08:34 AM ET (US)
I do not know. I will be calling the dealer today to ask them why they did that. I noticed it after we picked up the boat. I did find motor test from Whaler and they were done in the 3rd hole.
D37 posted 07-23-2007 08:57 AM ET (US)
I called the dealer and they said the following. They knew the original motor was mounted in the third hole. But when they checked the boat based on the measurements per Mercury engine mounting recommendations it came out that it should be mounted in the first hole. I told them that if I find out that Whaler recommends that it should be in the third hole they need to remount the motor.
Tom W Clark posted 07-23-2007 09:44 AM ET (US)
Your dealer is an idiot. Have him raise the new motor to the third set of holes.
Slower acceleration, slower top speed, lousy handling, an increased propensity to porpoise and transom spray are all side effects of a motor mounted too low.
Also make sure the dealer does not stick you with a crappy aluminum propeller.
Casco Bay Outrage posted 07-23-2007 10:35 AM ET (US)
My thoughts exactly, thank you Tom!
Sal DiMercurio posted 07-23-2007 11:48 AM ET (US)
I agree with Tom 100%, except the price of the engine dosen't usually include a s/s prop.
Tom, I have a buddy [ John ] that's going to Tacoma this week, [ should be there at least 5 days ].
He needs a Stiletto, I gave him your number, he's a friend & good people, see if you can help.
Thanks.
Sal
Rob Schmidt posted 07-23-2007 12:01 PM ET (US)
Tom, quit beating around the bush, and tell us what you really think ;-)
Tohsgib posted 07-23-2007 12:55 PM ET (US)
I agree with Tom but also if you don't mind me asking...why did you repower so soon? 15hp is not enough reason to spend the money and I doubt performance will be any different from a 135.
Perry posted 07-23-2007 01:07 PM ET (US)
The 15.5 X 17 Mirage prop that came with your 135 Optimax is the same prop that Boston Whaler installs on the 150 Optimax on your boat. If it is still in good shape you can use it on your new motor.
D37 posted 07-23-2007 01:53 PM ET (US)
Thank you all for giving advice. I was pretty upset when I saw the different motor position. I repowered because my Uncle hit a rock shoal with the boat. Damage was high enough for me, actually him to kick in another 1000 to the amount we got from insurance to get a new motor with 3 year Mercury protection on it. I wanted the 150 because of test results published by Whaler. My wife and I loved the 135 Optimax. We had zero problems the 3 years we had the motor. The goal was to hold plane at lower speed and get on plane faster. Which according to Whaler the 150 does this at 500 to 750 RPMs less than the 135. I can tell you that even though it is in the incorrect position the performance of the 190 Nantucket with the 150 Optimax far exceeded my expectation. Having only 1.5 hours on the new configuration, I love it. I am sure it is all due to the different gear ratio of the motor. The boat is on an Island now so the motor will not get remounted until fall, when it comes back off and goes into storage. The new prop is SS same as recommended by Whaler, Believe it or not they (the dealer) said they called Whaler to coordinate the prop size and motor position. Whaler has not responded yet. When they do I will let you all know what they recommend. Thanks again, Dave
D37 posted 07-24-2007 08:15 AM ET (US)
Here is the reply from Whaler. They also attached a screen shot of the engineering drawing showing the recommended mounting. However, I can not attach it to this responce. Tom, can I email it to you for posting?
Dave
Whaler would mount both the 135 and 150 Optimax in the third hole (see below) for best performance.
The lower engine mounting may assist with less prop "blow out" when turning at higher speeds, however, it may also
reduce top speed along with rpms at Wide Open Throttle.
If you haven't already, you might take the boat out for a run (as typically loaded) and write down the
performance information (planing capabilities, any porpoising, WOT, etc) and then determine if
you would like the dealer to raise the engine.
Binkie posted 07-24-2007 08:26 AM ET (US)
Contrary to what some boat owners think, boat dealers are not all knowing gods. Some are better than others just as in all businesses. Fortunately D37 is an informed owner, and would question the dealers mistake.
Rich
Tom W Clark posted 07-24-2007 10:08 AM ET (US)
Dave,
Sure, email what you have and I'll see what I can do with it.

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Author	Topic: Engine Mounting Height
D37	posted 07-23-2007 07:47 AM ET (US) We just had a 2007 150 OptiMax put on our 190 Nantucket. The old 135 OptiMax was installed in the third hole, the 150 is installed lower in the first hole. What is the difference and how does this effect performance. Should I have them reinstall it in the third hole? Thanks
jimh	posted 07-23-2007 08:29 AM ET (US) Boston Whaler very likely conducted a lot of testing to determine the best mounting height for the motor on your 190 NANTUCKET, and that is where they mounted the original motor. It seems rather odd that you would just discard that advice and choose a new mounting height for the replacement motor, which is more or less identical in its dimensions and gear case as the original. I am just curious, but on what basis did you or the dealer installing the motor decide that you ought to change the mounting height?
D37	posted 07-23-2007 08:34 AM ET (US) I do not know. I will be calling the dealer today to ask them why they did that. I noticed it after we picked up the boat. I did find motor test from Whaler and they were done in the 3rd hole.
D37	posted 07-23-2007 08:57 AM ET (US) I called the dealer and they said the following. They knew the original motor was mounted in the third hole. But when they checked the boat based on the measurements per Mercury engine mounting recommendations it came out that it should be mounted in the first hole. I told them that if I find out that Whaler recommends that it should be in the third hole they need to remount the motor.
Tom W Clark	posted 07-23-2007 09:44 AM ET (US) Your dealer is an idiot. Have him raise the new motor to the third set of holes. Slower acceleration, slower top speed, lousy handling, an increased propensity to porpoise and transom spray are all side effects of a motor mounted too low. Also make sure the dealer does not stick you with a crappy aluminum propeller.
Casco Bay Outrage	posted 07-23-2007 10:35 AM ET (US) My thoughts exactly, thank you Tom!
Sal DiMercurio	posted 07-23-2007 11:48 AM ET (US) I agree with Tom 100%, except the price of the engine dosen't usually include a s/s prop. Tom, I have a buddy [ John ] that's going to Tacoma this week, [ should be there at least 5 days ]. He needs a Stiletto, I gave him your number, he's a friend & good people, see if you can help. Thanks. Sal
Rob Schmidt	posted 07-23-2007 12:01 PM ET (US) Tom, quit beating around the bush, and tell us what you really think ;-)
Tohsgib	posted 07-23-2007 12:55 PM ET (US) I agree with Tom but also if you don't mind me asking...why did you repower so soon? 15hp is not enough reason to spend the money and I doubt performance will be any different from a 135.
Perry	posted 07-23-2007 01:07 PM ET (US) The 15.5 X 17 Mirage prop that came with your 135 Optimax is the same prop that Boston Whaler installs on the 150 Optimax on your boat. If it is still in good shape you can use it on your new motor.
D37	posted 07-23-2007 01:53 PM ET (US) Thank you all for giving advice. I was pretty upset when I saw the different motor position. I repowered because my Uncle hit a rock shoal with the boat. Damage was high enough for me, actually him to kick in another 1000 to the amount we got from insurance to get a new motor with 3 year Mercury protection on it. I wanted the 150 because of test results published by Whaler. My wife and I loved the 135 Optimax. We had zero problems the 3 years we had the motor. The goal was to hold plane at lower speed and get on plane faster. Which according to Whaler the 150 does this at 500 to 750 RPMs less than the 135. I can tell you that even though it is in the incorrect position the performance of the 190 Nantucket with the 150 Optimax far exceeded my expectation. Having only 1.5 hours on the new configuration, I love it. I am sure it is all due to the different gear ratio of the motor. The boat is on an Island now so the motor will not get remounted until fall, when it comes back off and goes into storage. The new prop is SS same as recommended by Whaler, Believe it or not they (the dealer) said they called Whaler to coordinate the prop size and motor position. Whaler has not responded yet. When they do I will let you all know what they recommend. Thanks again, Dave
D37	posted 07-24-2007 08:15 AM ET (US) Here is the reply from Whaler. They also attached a screen shot of the engineering drawing showing the recommended mounting. However, I can not attach it to this responce. Tom, can I email it to you for posting? Dave Whaler would mount both the 135 and 150 Optimax in the third hole (see below) for best performance. The lower engine mounting may assist with less prop "blow out" when turning at higher speeds, however, it may also reduce top speed along with rpms at Wide Open Throttle. If you haven't already, you might take the boat out for a run (as typically loaded) and write down the performance information (planing capabilities, any porpoising, WOT, etc) and then determine if you would like the dealer to raise the engine.
Binkie	posted 07-24-2007 08:26 AM ET (US) Contrary to what some boat owners think, boat dealers are not all knowing gods. Some are better than others just as in all businesses. Fortunately D37 is an informed owner, and would question the dealers mistake. Rich
Tom W Clark	posted 07-24-2007 10:08 AM ET (US) Dave, Sure, email what you have and I'll see what I can do with it.