Outboard advice for 5.4m Aluminium

[Bitola]

Hi,

I'm in the process of throwing a heap of cash at my old 1979 De Havilland. Completely gutting, re-welds, paint, floors, the works. I'm looking to put some new power behind it and am hoping for some advice. Currently has a '02 75HP Mercury.

I'm thinking of going bigger (towards 100/115) and looked into the new Mercury 4 strokes. I've noticed that from 75-115 they are all the same block. Is this correct? If so, does that mean that the 115 will be tuned and working harder than the 75......leading to faster wear and tear???

Appreciate any info and/or better options.

Thanks in advance.

Kaine

[ericcs]

Is the boat rated to 100/115hp, if it's not, there are legal implications. if it is, can the boat cope with the added weight of the 4stroke, will a big jump from the 2st.

[Chris Tucker]

A 40 year old boat is unlikely to have a builders plate or official rating. Have a look at the new Suzi 100 it will be much closer to your current engine weight.

[Bitola]

Thanks Eric/Chris.

Can't find a plate. Spoke to a dealer and he said that there is only about 25kg difference and it wouldn't be a problem.

I'll look into the Suzi. Any ideas about the wear and tear issue? It seems if the Mercs have the same components and block that it means that the 115 would just be working everything harder.

[Skusto]

No not really In regards to the merc as it's a 2.1 litre donk, they are a big displacement engine for the smaller hp models. Will give you plenty of enjoyment for years to come.

Just remember most of these outboards will happily run at 5000 rpm all day every day just depends if you want the fuel bill that goes with it.

For a rec fisher there would not be many that would be able to wear a motor out normally failures start due to age and maintenance.


Sent from my iPhone using Ausfish forums

[gazza2006au]

You need to take into consideration on these old girls, How will the extra ponies handle? if your looking for more speed u could probably just swap the propeller or add TT not everyone likes to go flat out alot of boaters like to minimize fuel consumption

a brand spanker of same size motor that u already have will have a good percentage of new fresh power over the old girl