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Author Topic:   MENEMSHA, 75-HP Four-cycle

minitauk85 posted 03-12-2008 03:00 PM ET (US)
I may have the line on a newer 75-HP four-cycle outboard motor to mount on my 1969 Menemsha. Any advice or other thoughts on performance? Estimates on top end speed? Not sure of the brand or any other details for that matter. Just wanting some feedback--k
Perry posted 03-12-2008 04:52 PM ET (US)
[The performance with a MENEMSHA] would depend on what make of 75-HP four-cycle motor it is.
Nauti Tauk posted 03-12-2008 07:00 PM ET (US)
Kev,
Not so much for speed, but for load carrying and an easy effort cruise speed my opinion would be a 90-HP four-cycle or Yamaha 90-HP two-cycle. I'm thinkin you're gonna need the extra horsepower. Just my .02. See you mid April.
jimh posted 03-12-2008 07:50 PM ET (US)
There are many reports of satisfactory performance with classic 16-foot hulls and four-cycle motors in the 70-HP range. The concern is not particularly for performance but more with transom weight. With a MENEMSHA that already has extra weight from the cabin superstructure, you should consider the engine weight and how the overall trim of the hull will be affected.
Tohsgib posted 03-13-2008 09:50 AM ET (US)
Is it one of those "lake" Mercs for $3500 or ?? I think it will be plenty and hit mid 30's. A 90 Yamaha 2 stoke will be about equiv but I think the extra weight of a 4s will be beneficial on that bow heavy model.
minitauk85 posted 03-13-2008 03:39 PM ET (US)
I wish I could give more information and specifics about this motor, but my mechanic hasn't even seen it yet! Am I correct that a 4 stroke is significantly heavier than a 2 stroke? I agree that more horsepower is desirable in general, and I believe the cuddy, head and console add about 300 lbs to the front of the Menemsha. Don't want to over do it on total weight with a huge motor, but at the same time I don't want to be underpowered! I guess I should have titled this thread "suggestions for Menemsha power"-k
gcarlil posted 03-13-2008 06:17 PM ET (US)
Kevin, I'm running a 1978 90 hp inline six Merc on my mid 70's hull 17'. WOT 38 mph with GPS. Pleased but wish I had a 115 on the transom. With the additional weight I think you should go max hp or over. We could put 300 lbs. in the bow of my boat and see what happens. Great day to go fishing low 70's on Lanier today rain tomorrow.
George
Casco Bay Outrage posted 03-13-2008 06:34 PM ET (US)
Kevin -
Here is a good article listing all the horsepower and weights when selecting an engine for a classic 16 or 17 foot Boston Whaler:
http://www.whalercentral.com/readarticle.php?article_id=5
CBO
jmorgan40 posted 03-14-2008 03:54 AM ET (US)
Kevin,
I was speaking to Robert this week and he said he had a line on that 4 stroke for you. I am also afraid that the xtra weight on an older 60's hull may be too much combined with the cabin. But lets see what he has and what the weight is since it is a 75 hp. You may be OK but don't expect the blazing speed you saw with the 15' hull. 2 more cents to chew on. Let me know how fishing was today and the ramp condition
minitauk85 posted 03-14-2008 05:09 AM ET (US)
George- I could stand up front with a couple cases of beer-should be just shy of 300 lbs! I appreciate the offer!
CBO- Looks like I should expect roughly 40-50 pounds weight increase from a 4 stroke. Thanks for the link.
Joe-I wasn't able to get a hold of Robert yesterday. Hopefully today, but I don't think he's going to know anything until Monday. As for fishing, I'm at home with a cold today. Talk about aggravating, haven't fished in 2 weeks, going on 3... argh....k

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Author	Topic: MENEMSHA, 75-HP Four-cycle
minitauk85	posted 03-12-2008 03:00 PM ET (US) I may have the line on a newer 75-HP four-cycle outboard motor to mount on my 1969 Menemsha. Any advice or other thoughts on performance? Estimates on top end speed? Not sure of the brand or any other details for that matter. Just wanting some feedback--k
Perry	posted 03-12-2008 04:52 PM ET (US) [The performance with a MENEMSHA] would depend on what make of 75-HP four-cycle motor it is.
Nauti Tauk	posted 03-12-2008 07:00 PM ET (US) Kev, Not so much for speed, but for load carrying and an easy effort cruise speed my opinion would be a 90-HP four-cycle or Yamaha 90-HP two-cycle. I'm thinkin you're gonna need the extra horsepower. Just my .02. See you mid April.
jimh	posted 03-12-2008 07:50 PM ET (US) There are many reports of satisfactory performance with classic 16-foot hulls and four-cycle motors in the 70-HP range. The concern is not particularly for performance but more with transom weight. With a MENEMSHA that already has extra weight from the cabin superstructure, you should consider the engine weight and how the overall trim of the hull will be affected.
Tohsgib	posted 03-13-2008 09:50 AM ET (US) Is it one of those "lake" Mercs for $3500 or ?? I think it will be plenty and hit mid 30's. A 90 Yamaha 2 stoke will be about equiv but I think the extra weight of a 4s will be beneficial on that bow heavy model.
minitauk85	posted 03-13-2008 03:39 PM ET (US) I wish I could give more information and specifics about this motor, but my mechanic hasn't even seen it yet! Am I correct that a 4 stroke is significantly heavier than a 2 stroke? I agree that more horsepower is desirable in general, and I believe the cuddy, head and console add about 300 lbs to the front of the Menemsha. Don't want to over do it on total weight with a huge motor, but at the same time I don't want to be underpowered! I guess I should have titled this thread "suggestions for Menemsha power"-k
gcarlil	posted 03-13-2008 06:17 PM ET (US) Kevin, I'm running a 1978 90 hp inline six Merc on my mid 70's hull 17'. WOT 38 mph with GPS. Pleased but wish I had a 115 on the transom. With the additional weight I think you should go max hp or over. We could put 300 lbs. in the bow of my boat and see what happens. Great day to go fishing low 70's on Lanier today rain tomorrow. George
Casco Bay Outrage	posted 03-13-2008 06:34 PM ET (US) Kevin - Here is a good article listing all the horsepower and weights when selecting an engine for a classic 16 or 17 foot Boston Whaler: http://www.whalercentral.com/readarticle.php?article_id=5 CBO
jmorgan40	posted 03-14-2008 03:54 AM ET (US) Kevin, I was speaking to Robert this week and he said he had a line on that 4 stroke for you. I am also afraid that the xtra weight on an older 60's hull may be too much combined with the cabin. But lets see what he has and what the weight is since it is a 75 hp. You may be OK but don't expect the blazing speed you saw with the 15' hull. 2 more cents to chew on. Let me know how fishing was today and the ramp condition
minitauk85	posted 03-14-2008 05:09 AM ET (US) George- I could stand up front with a couple cases of beer-should be just shy of 300 lbs! I appreciate the offer! CBO- Looks like I should expect roughly 40-50 pounds weight increase from a 4 stroke. Thanks for the link. Joe-I wasn't able to get a hold of Robert yesterday. Hopefully today, but I don't think he's going to know anything until Monday. As for fishing, I'm at home with a cold today. Talk about aggravating, haven't fished in 2 weeks, going on 3... argh....k