Ski boat project questions

[Frosty]

If it was just a ring why didnt he put it back together and how many bolts did he rip out of the alluminium. You got all the rollers from the bearings ---sure?

Rarely do this things go back together well.

But at 400 dollars.

 

[tunnels]

It's very rare to snap a ring and not scratch the crap out of the bore, suggesting someone isn't telling the truth. I wonder what else he's not being honest about. It sounds like a good deal, but I'd want to see the bore.

Agreed 50 mm on the transom core is wise. The earlier 38 mm recommendation was understandably for the smaller engine.

Not really !! have seen a ring in two pieces just sit in the groove and the only tell tale sign was compression as down on one cylinder and thats all even in a car engine i always used to pay special attention to fitting rings and allow a little extra gap . if the absolute minimum clearnace is used you only have to over heat the motor once and that will compress and snap a ring . Use to always know because if a radiator blew and the car was smoking after it all the rings lost there tension and used to find the top rings broken !! jUST HAD TO re-ring the pistons !! lightly hone the bore with a fine hone to make the rings bed quickly and 500 miles later performance was better than new !!

So check the water pump impeller and see if all the vanes are there or the key hasnt been stripped out of the centre , Id pay special attention to the reeds on the intake as well if the motor is getting a little long in the tooth the reeds could need turning over so the seat properly . makes for better starting and low speed running just over idle !!. Would pay to do a complete over haul anyway and replace seals and gaskets ! two strokes dont like any kind of airleaks any where so just for piece of mind ! He has a dvd service manual with it .

 

[Frosty]

Your talking car engines --this an alloy block with chrome bores.

A ring is round, it is not when it broken.

He did not say if this is the old Black Max v6.

 

[whitepointer23]

for that price it must be an old tower of power straight six, it was probably run on unleaded which killed it. if you rebuild it and use a lead replacement additive when you fill up it will be a good engine. the carbys can be a pain in the arse because there are so many of them. i had a blueband which never had any drama's.

 

[tunnels]

for that price it must be an old tower of power straight six, it was probably run on unleaded which killed it. if you rebuild it and use a lead replacement additive when you fill up it will be a good engine. the carbys can be a pain in the arse because there are so many of them. i had a blueband which never had any drama's.

If it was a tower of power it would be a collectors itam !!
But its 25 inch so must be a vee 6 motor and recent as well because they havent been around that long !! .

 

[Frosty]

The black max v6 came out in the 70's

 

[tunnels]

this is interesting !!!!

http://www.maxrules.com/models/Merc_model_files/115-150.html

After cruising for half and hour looking at parts and bits of all sorts i came to the conclussion that the serial number is very very important to possitivly identifying your motor and specially when you ordering parts for anything on the unit !!! so find the plate , take a picture of it and store it in your computer in a really safe place !!!
I did the same thing with my car and i printed all the info and when i go looking for bits i have everything on paper in my hand Japanese cars there are so many differant models of things i also take a picture of the parts i want to buy as well of its possible to make sure i get waht i really want . I worked in a ford parts department for 14 years and new every part for every car, truck or tractor and hardly ever had to consult a parts book ever that was before the days of computers . Now you take a part and show it to the guy behind the counter he has a hissy fit and spends half a day looking for a part number .

 

[whitepointer23]

there are thousands of straight 6 mercs in oz, still quite popular. the last model was around 1988,89 i think.

i have never seen a black max for $400.

 

[whitepointer23]

now i think about it, it was only available up to 115 hp once the black max came on the market.

 

[whitepointer23]

It's very rare to snap a ring and not scratch the crap out of the bore, suggesting someone isn't telling the truth. I wonder what else he's not being honest about. It sounds like a good deal, but I'd want to see the bore.

Agreed 50 mm on the transom core is wise. The earlier 38 mm recommendation was understandably for the smaller engine.

should be able to hone a scratch out or bore and go oversize.

 

[aussiebushman]

Motor rebuild and mounting bracket

I'm getting the model/serial number and pictures of the bore tonight, before paying any money. My guess is that Brendan is right - someone ran it on E10 and that is known to kill the best of the older engines. I run my 91 Range Rover on 98 octane unleaded (no ethanol) but for the outboard, the LRP additive might be necessary

For $400 what have I got to lose? The parts will be worth more that than if I decide not to rebuild it.

On a different subject, how about this Gill bracket (or similar) mounted on a 50 mm thick (beefed up) transom? It would eliminate the cutout, most of the splashing when in reverse and make the mounting far simpler. The Armstrong bracket looks a bit more solid and could be fabricated in stainless without too much trouble

Alan

 

[aussiebushman]

Probably answered my own question when I found the thread many of you guys had already created at

http://www.boatdesign.net/forums/outboards/outboard-bracket-advantages-disadvantages-38396.html

 

[tunnels]

Been there and done that !!

Brackets !! some are good some are not so good depends how far back you want to push the motor ?? 600 mm is a long way back and you will need the 25 inch to keep the motor out of the water . remeber the further back the motor the more the back of the boat will go down inthe water and if you havent got much feeboard you could be sunk very quickly. 300mm or 400 mm is not so bad ! will have to move the fuel tank forward and the battery as well
To ballance my small boat i have 3 tote tanks up under the fore deck to offset a part of the stern down!! Good when they are all full OF FUEL but as they empty then the bow comes up .
The power tim on the motor can lift the stern when you go backwards just raise the trim on the motor its never a problem . same with low speed trim and tuck the motor right in as far as it will go it will help lift the back of the boat .
Its like everything its what you get used to and after a while just comes natural !!.
there are some simple and very basic rules when setting the bracket on the transom and when fitting the motor to the bracket . Is best to draw everything out full size and accurate on a sheet of plywood to get everything close to where it should be right from the word go !!!
General rule is for every 300 mm from the back of the transom the motor is ,the motor can be lifted 12 mm !!! i will draw out and post a picture so you get what i am saying .
Your motor on a 600mm bracket could be raised 35 mm above the line of the keel of the boat !!
Come back to a 400mm bracket and might be closer to 25 mm above .
Remember its just a starting point for how you set up the boat that will determin the motors final resting place where the motor is best suited and dosent do anything silly .
Personally i would go for the closed in box type bracket as it will help a lttle with floatation and make the going to stern thing a little more pleasent !! Adding a bracket and a big motor with a 25 inch bracket to the transom will have to be really built strong and have lots of bolted support brackets inside the hull going down onto the longtudinal stringers !! and bracing to pick up the lower bolts of the bracket all the way across the transom right out to the hull sides . this is serious stuff . seeing you have lost freeboard the aft deck will be there to keep the water out and may have to even have an upstand around the inside edge to help keeing water at bay !!
A bracket changes the performance and handling and the power trim now becomes something you will have to get used to useing alot !! learning what you can do and what you should do with it . you will need seat time but the thrill at the end is completely worth all the effort believe me !!


AND if you do settle for a bracket i would deffinitly try to find a hydrualic steering kit with pump, hoses, and fitting and the two way ram !!! this is the unit i fitted to my boats but there are others
http://www.teleflexmarine.com/products/hydraulic-new/outboard-new/seastar-front-mount/

 

[tunnels]

steering

Its small and tidy and fitted straight on the motor didnt have to change a thing . but like i said there are othes
something else to read http://www.marinesteering.net/hydraulicsteering.htm

 

[aussiebushman]

Just got the plate details and pictures. Checked it on the Internet and it looks like a 1975 straight 6 2-stroke 150 Hp with serial number 4257820

Alan