135 mariner on a 16ft swiftcraft stingray

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jamiebrant

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hi everyone im from australia. i just cooked my 75hp chrysler on last fishing trip had to use two manpowerd oars for a couple of km's was not fun at all. all apart of the fun though. i have just found a 91 model mariner 135 v6 in tip top condition with 25in leg my transom has a 16mm ally plate and it makes the transom 23.5 in is this possible? or is the engine to big? to powerfull ? leg to long .some advice would be greatly appreaciated.i use the boat for both fishing and skiing cheers.
 
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Chris1956

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Re: 135 mariner on a 16ft swiftcraft stingray

Do they have max HP ratings on boats in Oz? if so, the HP question is pretty easy. If not, what the is beam on that boat? If the beam is wide, and the hull built strong it might be OK.

Normally the transom would be close to either 20" or 25". An older 16 footer would usually have a 20" transom. Are you measuring from the top of the transom to the bottom of the hull in the exact center?
 
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jamiebrant

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Re: 135 mariner on a 16ft swiftcraft stingray

thanks for that info mate im not to sure where it says on the boat what hp its rated to ?i think that we do have these laws but not sure its my first boat so im pretty new to this thats why i asked people who know what there on about. i think the transom was a 20in but they have raised it with the aluminium plate it measures 23.5 from the top of the plate to the lowest point and the engine clamp has about a 2 in gap under it so its not sitting on the plate im not to worried about the power just worried about ripping the transom off if this is possible .cheers
 
redjmp

redjmp

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Re: 135 mariner on a 16ft swiftcraft stingray

Well I think you would be right at the max for that boat with a 135.

You would want to mount it so that the anti-cavitation plate is level with or just slightly higher the the keel. If it sticks out an extra 1.5 inches it will be a lot of drag in the water and will knock 5-10 mph off your top speed.

How is your 75 mounted? Is it a 25" leg? That is an odd size for a transom at 23.5".
I don't think that a normal 20" leg would keep enough of the prop in the water when planing to keep it from cavitating.

How does it run with the motor you have now?

The real question is why the plate? Is it covering up a weakened transom?
 
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jamiebrant

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Re: 135 mariner on a 16ft swiftcraft stingray

when the 75 was going it did 35 mph on glass the leg must be 25 in on it. my mate who is a fiberglasser by trade said that its pretty solid for its age and it would take a few weekends to do if needed replacement the plate is just to raise it .in all i was worried about the engine sticking up to high being to heavy or to much power for the little boat cheers.
 
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jamiebrant

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Re: 135 mariner on a 16ft swiftcraft stingray

i think i will change my ideas i want my boat to be more safe than fast .i just found a brownband merc 90hp 20 in shaft are these a good engine and is it 90 at the prop or the fly? thanks again for your help.
 
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Chris1956

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Re: 135 mariner on a 16ft swiftcraft stingray

Brownband is probably propshaft rated.
 
Fregata

Fregata

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90hp Merc. inline6 on a 16ft swiftcraft stingray

90hp Merc. inline6 on a 16ft swiftcraft stingray

90hp (propshaft) Brownband Merc. inline6 are 1984 or 85 mod. 1983 was blueband, and -85 was the last prod. year for this motor. If you have the serialnumber available, the we can find out with year it is.

Anyway, this is a great motor! (...if the previous owner took good care of it).
 
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jamiebrant

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Re: 135 mariner on a 16ft swiftcraft stingray

thanks for that info. i went to check out the motor at my local marine shop and the bloke had just traded it in on a brand new one. I inspected it made sure it was cold when i got there started no worries no hot spots was pumping water fine and NO corossion anywhere on the engine just a little on the lead plate under the transom clamp. i pick it up on wednesday.the funny thing is it still got half the original sticker on the side of the transom clamp. I am hopeing its been well looked after.
 
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