Engine too heavy?

[Herman Melville]

Hi All,

I have a Yamaha 90A which weighs 125kg on the back of my 5.5m avon seasport

Its very broken and am putting on a new engine

I am thinking of Yamaha F100A - which weighs 166kg

Is that extra 40kg a big deal.

It sounds like it might be a big deal.

The weights and measures plate on the transom does not specify a max weight for the engine.

Cheers

[Pikey Dave]

Originally Posted by Herman Melville

Hi All,



I have a Yamaha 90A which weighs 125kg on the back of my 5.5m avon seasport



Its very broken and am putting on a new engine



I am thinking of Yamaha F100A - which weighs 166kg



Is that extra 40kg a big deal.



It sounds like it might be a big deal.



The weights and measures plate on the transom does not specify a max weight for the engine.



Cheers

What’s the highest output engine in that weight class of Yammie? I.e is the 100 the same block & weight of say, the 115?

[rik_elliott]

My friend has a 90hp merc 4s from 2004 on an apex 5.5. Those old 4 strokes were even heavier at 176kg ish. I know it doesn't directly answer your question but context can help and it shows your engine isn't the heaviest out there.

I think cjj216 who used to post here had an adventure 5.6 with a 125 4s on it so I can't imagine even a heavy 100 will be too much.

[Herman Melville]

Cheers sounds positive

[Herman Melville]

Originally Posted by Pikey Dave

What’s the highest output engine in that weight class of Yammie? I.e is the 100 the same block & weight of say, the 115?

Yes seems 100 is same weight as 115

[Pikey Dave]

Originally Posted by Herman Melville

Yes seems 100 is same weight as 115

Put the 115 on them, no point carrying dead weight.

[davej]

Our 5,5 tornado has a 115 yam 2s which is 160 kg and seems fine. We do also hang a small Yamaha malta kicker on the back and again doesn’t feel heavy at the stern.

If you can go for the bigger engine.

[Herman Melville]

cheers all

Also just checking - if my 90A shaft code on the plate was 'L'....

then another Yamaha engine also with 'L' for the shaft code will fit my transom right ?

[whiskylee]

Originally Posted by Herman Melville

cheers all



Also just checking - if my 90A shaft code on the plate was 'L'....



then another Yamaha engine also with 'L' for the shaft code will fit my transom right ?

L = Long Shaft (20inch) aprox

XL = XL (25inch)

[whiskylee]

Originally Posted by Herman Melville

Hi All,



I have a Yamaha 90A which weighs 125kg on the back of my 5.5m avon seasport



Its very broken and am putting on a new engine



I am thinking of Yamaha F100A - which weighs 166kg



Is that extra 40kg a big deal.



It sounds like it might be a big deal.



The weights and measures plate on the transom does not specify a max weight for the engine.



Cheers

Is your boat a Avon seasport 545 ? If so max HP is 90

[Herman Melville]

Yes it is - Ok that is bad news.

What are the downsides from going over by 10hp ?

[Pikey Dave]

Originally Posted by Herman Melville

Yes it is - Ok that is bad news.



What are the downsides from going over by 10hp ?

Depends on your attitude to risk & your insurance company, if you have one. I told my insurance company that I was slightly overpowered & they asked me what the top speed was. They were happy with my answer & insured the boat.

[Swordfish]

..or you could buy my low hours 90 AETOL
https://www.rib.net/forum/f10/yamaha...-new-post.html

[Herman Melville]

thanks @swordfish looks like a nice engine but am going to go with the 100 - its at a boatbuilders in my marina so much easier

[Bigmuz7]

Originally Posted by Herman Melville

Yes it is - Ok that is bad news.

What are the downsides from going over by 10hp ?

Not a lot if insurance is ok and weight is good .. think of the slamming and knocks the boat takes every time you hit some wind and tide ? which wouldnt trouble it



The extra weight is only a concern when/if you are at anchor. I had a 135 2 stroke on a 5.8 once which needed the transom raised due to this problem. Try some ballast first if you are concerned if you anchor at sea

[paintman]

^^^
If that was the Mercury 135 V6 the manual for mine (late 80s Black Max) gives it as 172kg/378lbs.

It's a 17' Dory & not had an issue anchored bow on to wave, but if fishing on the drift & there's much wave I stream a drogue to keep the boat side on or slightly bow on to the wave or I'm likely to get some water over the lower part of the stern where the engine sits.
The weight does keep it low.

Incidentally, never anchor stern on to the tide run /wave direction as it will pull the stern down & you may well be swamped & sink.
One of the locals shot a string of pots & got the last section of rope to the dahn caught round the outboard's prop. Unable to free it that's exactly what happened.

[Davie]

Have you bought the Humber 5.5 and now selling the boat and trailer only on fb?

[Herman Melville]

No fitting a new engine to my Avon @Davie

[kingfishnz]

I have a mariner 90 2 stroke on my 5.4 and ive been told by a guy that replaced my tubes that they can take up to 115. I dont have a weight plate on my boat either

[Swordfish]

Originally Posted by Herman Melville

thanks @swordfish looks like a nice engine but am going to go with the 100 - its at a boatbuilders in my marina so much easier

Completely understand Mr. Melville! It would be not like me at all to try to dissuade you from an increase in power!