In a message dated 5/2/03 6:45:23 PM, rdawson@surewest.net writes:
Sorry if this is off topic and I know this subject gets totally hashed but I am in the market for a 4 stroke outboard for my M15 and need to know the transom height or how to measure it. My boat is an 89 model with the fixed motor mount.
I know that the Honda 2hp is all I need and is the bomb BUT, Stockdale Marine has a Briggs & Stratton 5hp for less $$ AND it has neutral, forward and reverse AND an external tank so I can cruise the river all day if no wind.
Thanks to anyone who responds. All comments welcome.
Ran Dawson
Ran, Thought I would weigh in on this topic. I have posted to this list on this topic many times in the past six or seven years. Rather than redo all of that here, you can read my thoughts direct from the Montgomery Owner's site: http://msog.org/surveys/2strokevs4stroke.cfm The latter portion addresses specific engine choices for the M15. There are also several helpful posts from others on the same site. A few things to add: While I have been very happy with the Honda 2, I have been looking at alternatives for a possible upcoming Alaska trip. I have no doubt that the Honda would suffice, but we may be traveling in tandem with a larger/faster boat, and I am concerned about slowing them down (in spite of other's claims of hull speed at 1/2 throttle or less, my experience in full cruising trim has been quite different). I also would love to have the option of an external tank, though my refueling system works quite well (see above article for description). I started to look at the current offerings, but decided that 5hp models were just too heavy, and were overkill power-wise. I was not only concerned for my back, but also for the hull-to-deck joint atop the transom. It may be coincidence, but I have seen several M15's with large outboards that also had separation at this joint (not thru-bolted at the transom as it is elsewhere) . If I were to risk the heavier outboard, I would go for the Yamaha 4hp/4- stroke. At 48 lbs, it is at least 7 or 8 lbs. lighter than the Honda 5 and the Tohatsu/clones offering. It offers both internal as well as external tank flexibility, and Yamaha has an excellent reputation as well as an extensive dealer/service network (far better than Honda worldwide). That said, I still think the Honda 2 or the new Yamaha 2.5 are the very best choices for the M15. If I were buying today, I might favor the new Yamaha 2.5hp. Claims are that it has significantly more power than the Honda 2 (more than the 0.5 hp difference would suggest), is more service friendly, and is extremely fuel efficient. At 37 lbs, it falls somewhat in the middle between the 28-30lb Honda 2 and the 48-60lb 4/5 hp offerings. The only drawback I can see is that the 2.5 is only available (at present) as a 15" shaft (short shaft). I am hoping to get a hold of one for testing and comparison to my Honda. My hope is that they will eventually offer a long shaft version. There is some disagreement as to the appropriate shaft length for the M15. In my opinion, the best choice will depend on use. I have been on M15's with both, and based on my experience with short shaft engines popping out in very rough conditions, I decided to go with the long shaft Honda. The cost of the added bite of the long shaft in rough water or when weight is forward is that it does drag more than the short shaft when on a starboard tack. Some have gone with adjustable mounts to counteract this. For reasons I won't go into, I prefer the stock mount. I have not found the modest drag to be worth worrying about (indeed, could not measure significant speed difference between no motor and slightly dragging motor, though it can be a bit noisy). When all is said and done, I may decide to just keep the Honda, as it really is a great little engine. As for the new Briggs & Stratton 5hp, I recently looked at it at Pacific Sail Expo. While cheap, it is somewhat ponderous in appearance and reportedly very loud. The real clincher for me was when I queried the rep and he told me that it should not be used in salt water!! I think the Honda is a much, much better option for a few dollars more. Measuring transom height: I assume you are asking because manufacturer's advertise there engines according to transom height. When I asked several dealers, I got several different answers. Some suggested that this is the measurement between the actual top surface on which the outboard rests (in the case of the M15, this would be the top of the mount) and the waterline. Others suggested that the lower measurement is a point at or near the cavitation plate of the motor. I ended up measuring the shaft length of a known quantity--my friend's Johnson 3.3 short shaft--and used that as a reference when comparing different shaft lengths. Whatever you do, don't trailer with any outboard affixed! I am quite sure that at least one of the separated hull/decks I saw was a result of such practice. Good luck whatever you choose! Scott Grometer, M15 #478 'bebe'