Conference vicki::boats

I have an old 1968 Mohawk 18 ft fiberglass boat.  It currently has a 105HP
Chrysler outboard motor which I would like to replace.  I was thinking about
getting a bigger engine like a 125 HP but when I mentioned it to the 
instructors at the Coast Guard Auxillary course they said that I might be
overpowering the boat.  It seems like you can get into alot of trouble by
overpowering your boat with the Coast Guard and the Insurance companies.

If you have an older boat with no capacity rating, how can you tell what
is the maximum size engine that you can put on it?  I want an engine that
can comfortably hold up to six people and still be able to waterski.

What would be a good brand of engine that can easily be serviced in the 
Leominster, Mass area?  Outside of Force, what kinds of engines would be
hard to get serviced in that area?

Does anyone know where I can get information on Mohawk, the maker of the
boat?  I think that they were out of New York.

								Rob.


< Note 158.0 by TRILGY::FLONNOY "DTN 521-6671 WRO1-2/D30" >
                          -< Re-powering older boats >-

    I have a 1969, 18' Classic tri-hull that we brought last year.
    The boat has some very high hours on it and we have thought about
    re-powering it and putting in a new interior over the next few
    winter months. The boat has a 130hp (dual Solex carb) Volvo/Penta I/O.
    And I am looking for advice on engines. Should we stick with
    Volvo/Penta or go with Mercury? I see a lot of newer boats with
    Mercury. Are they better? Should we upgrade from the four cylinder to a V6?
    Or is it just better to rebuild the one I have now? Thanks in advance!
     

    Rob,
    
    I don't think there is any way to know if you are "over powered"
    without getting the original specs for the boat. How good of shape
    is it in? Particularly the transome and gunwals near it. How heavy
    is the boat? What is the bottom configuration? (deep-v, semi-v,
    etc) Clearly a deep-v that is on the heavy side and in good shape
    can take more power.
    Also, you will get more speed per HP from an outboard than from
    an I/O. I have a 19' I/O with a 120Hp Merc. The dealer (a good one)
    said I would get the same power/speed from a 90 Hp Johnson OB. I
    would also guess that you would get more out of a new OP of the
    same HP than you do now out of the older 105! ie, a 110 Merc might
    give you 15% more power. The new OBs are really quite strong these
    days.
    There is a formula from your USCG AUX course manual for calculating
    the load carrying capacity for your boat. I can look it up if you
    want it. Let me know!!
    I suspect your instructor was a little concerned about the age of
    the boat. A new 18' should take a 125 with no sweat. If your boats
    structure is very good, I would not expect any problems.
    Just thought of another issue---the weight of the engine and the
    freeboard. Would a 125 Hp weigh enough to push the stern too far
    down in the water? Most OB boater problems come from swamping over
    the stern---something to think about.
    
    Good Luck
    Don  

    
    
    reply to 158.0
    
    I would think that a 130HP on an 18' is plenty of power. the decision
    to repower or rebuild depends on the condition- is the outdrive
    in good shape? if the boat is used in salt water,and doesn't have
    freshwater cooling,the manifold and housings could be badly corroded
    and not worth the effort. The question of investing in a whole new
    I/O is one of is the investment worth it on an older boat?? 
     If the current power is adequate, I would be tempted to rebuild-
    OSCO makes reasonably priced replacement manifolds and risers
    and any good machine shop should be able to do the head, and rebore
    the block, do the crank, etc.
    
    
     The basic difference between a marine block and an automotive block
    are the cam, and using marine gaskets instead of automotive gaskets.
    
    I went throug this decision on my 22'NOrth American with a 225 OMC
    (chevy 307 block) which was used in salt water w/o FWC. The block
    was shot- too far corroded to be worth rebuiling. I opted to putin
    a new 350 chevy block and heads, changed the gaskets,rebuilt the
    acessories, had the outdrive redone(new bearings/seals/water pump),
    and replaced hoses,wiring,etc. THe problem in replacing this outdrive
    was that extensive transom work would have to had been done due
    to the different mounting arrangements for the newer model outdrives.
    
    THe savings allowed me to put in FWC, trim tabs(this older outdrive
    does not have trim, only power tilt), and have enough left over
    to re-upholster all the seats and cabin cushions.
    
    I didn't suffer from lack of power(the origional engine was 225HP),
    but te 350 gives a lot better performance, and doesn't seem to strain
    as much as the 307- the difference in price between a new 307 and
    a new 350  wasn't worth  mentioning.
    
     I could hjave gotten by even cheaper If I ha bought a rebuilt block
    and heads- but I wanted the 4 bolt mains.
    
    Just some thoughts- The work and grief involved with a complete
    repowering with a whole new outdrive just wsn't worth it.
    
     The one hooker in here is that if you keep the old outdrive assembly
    and rebuild the engine, wht is the availability of parts for the
    outdrive- the engine itself is easy to change out.
    
     My decision was easy, sice the original boat was available with
    a 4cyl chevy, a 6cylinder chevy, a 225HP v/8 and a 245HP v/8
    
    
    Just some thoughts
    
    
    gh
    
    
    

    re: -1
    
    Thanks for the advice ... I think it'll just be a rebuild based
    on some checking we did! 

    Steve Matscherz
    Field Service in Pittsburgh Pa
    
     I recently purchased a 12' fishing boat, it came with an old (seized)
    Chriscraft motor (about 30 years old). After spending some time
    unseizing the motor and cleaning points, carb etc. It finally runs.
    I'm not so sure of the water pump though. When I run it I don't
    run it for too long, I'm afraid that the motor will seize up again.
    The motor was seized the first time because water had gotten in
    the cylinder and froze the piston.  I tried calling a dealer about
    this engine and all I got was the old line "too old, company went
    bankrupt and no parts available". They even went so far as to suggest
    that I use it as a "boat anchor"! I would rather get it running
    and be able to use it for at a couple of years. 
      What I am looking for is someone who knows of anyplace that may
    have old parts for old motors. Specifically the water pump that
    is used on the (9.9? not sure if the power is correct). I have removed
    the pump and it is not like most boats. It looks like a donut with
    a notch taken out of it.
    
    
    		Steve M in the Pitts....
    PS motor is a Chris-craft , Model: Challenger

Mod's note: I've taken the base note posted by the author, broken it 
            up into several specifice questions, and moved each question
            to the appropriate existing topic.   /Rick

================================================================================
Note 999.0               1st boat that belongs to ME...                  1 reply
MR4DEC::FBUTLER                                      54 lines  26-JUN-1992 08:03
--------------------------------------------------------------------------------
	Well, after hours of pouring over this notes conference, I've
	finally taken the plunge.  A low end plunge, but for me, still
	a plunge.  

	Last night I bought a 1976 Grady White Bowrider hull (model 178)
	that has been stripped (no motor, no carpet, no seats, etc.) I
	specifically chose this route because I enjoy "projects".  The 
	hull came with a Shoreliner trailer that has been rebuilt (new 
	bearings, tires, paint, bearing buddies, lights etc.)  My usage
	will include fishing, both salt and fresh, and family outings.

	So.  Now the fun begins.  It's obvious that the folks that part-
	icipate in this conference have a wealth of knowledge and as you
	can imagine, I have a "wealth" of questions which I will try to
	keep somewhat organized...

	Repowering:

	The boat comes with a blown 70 horse Evinrude.  I've talked to 
	various folks and most have said that the boat needs more power
	(probably the reason the 70 blew).  I've located two potentials
	so far...1) rebuilt 1981 Evin. 115 with 0 hrs for $2000. and 2)
	1986 Evin 110 with "less than 30hrs, needs gd tune-up".  The boat
	is rated for 130hp.  Also found a 1973 Merc 115 with "low comp-
	ression in #3 cyl." but don't feel comfortable with an engine that
	old.  I've also been told to stay away from Merc's built before 
	the mid-80's as I would spend more time trying to keep them 
	running than enjoying the boat.

	Looking forward your responses, (even from those that think/know 
	I'm nuts)...