Mercury 75hp or Mariner 60hp

buzz · 07 June 2015, 20:55

Hi,

Looking at buying my first rib and have been looking at a Humber Assault 5m as it will fit in my garage. Will be used on salt water.

The one I am think about is fitted with a 2007 Mercury 75hp 2 stroke, are these engines any good?

Or I may also have a change of one with a 2004 Mariner 60hp 4 stoke, would be a better choice of engine?

I know there are a lot of things to take into consideration but what sort of fuel consumption do you think I would get out of these engines?

Thanks

Searider · 07 June 2015, 21:01

Hi Buzz,

What sort of use are you looking at?

Rescue boat?
Fishing with just you and a mate?
Towing a ringo?
Long distance?
Heavily loaded - 4 or 5 people?

The 4 stroke will be more frugal but a little less enthusiastic also!

buzz · 07 June 2015, 21:21

Not looking to tow a Ringo or fish it will mainly be used to play about with 3 or 4 people and to act as a safety boat for the local rowing club.

Not to concerned about the fuel as it will not be getting used to much. The many thing is if they are good reliable engines.

Searider · 07 June 2015, 22:05

Hi Buzz,

I had a Mariner 90hp 2 stroke (basically the same engine as the 75hp Mercury) on my 5.4 Searider and it was a great engine and never skipped a beat.
I think this would be a good engine for your boat.

The 4-stroke may be a better choice if you are doing lots of sitting about at idle. HOWEVER, the engine is older. I don't personally have any experience with the Mariner 60hp 4 stroke.

buzz · 08 June 2015, 12:47

The rib is about 350 miles away from where I am so trying to check out as must as I can before going to see it.

The owner said the engine is a 2007 2 stroke but looking around the internet the only pictures I can find of 2007 75hp mercury 2 stokes are a different shape and style. The pictures I can find that look like what the owner sent seems to be of older engines.

Looking at the picture could it be a 2007 engine?

Also does anybody know what the weight of this engine will be so I can check against the Humber maximum allowed?

Thanks for your help

Last Tango · 08 June 2015, 20:33

Had one just like this...was a 2004......never missed a beat, but I thought 2004 was the last year of this carburated model ??? Could be wrong though, I know the RLNI were still getting the 90HP carb model (Mariner badged) after this. Think the engine is 138KG

buzz · 08 June 2015, 20:53

That is about the age I was thinking it may be as looking at pictures on the internet showing engines of this style they range from 2000 to 2004.

Got the serial number ( OP119259 ) from the owner but cannot find it on any of the look up website.

phantom 19 · 08 June 2015, 20:53

The Mercury 75hp two stroke is a massive lump of an engine, a detuned 90hp which was already heavy for its class. It is also not the greatest engine with usual Mercury issues with the stator which will fail at some point, shonky lower shock mount castings, one piece block and head casting etc. gearboxes seem weak too, there is a ready market for second hand good gearboxes. The Yamaha 75/90 was/is infinitely better.

The mariner 60 fourstroke is a Yamaha powerhead that Mercury/mariner bought in and in their wisdom mated it to one of their own legs / gearboxes. They got the leg water pipe sealing arrangement wrong and used a iffy rubber seal which over time deteriorates and actually blocks the water pipe up. Resulting in having to lift the head and strip the leg down to component pieces to rectify. Otherwise it is a good powerhead although dated now with four carbs etc which if DIY fiddled with need setting up properly again.

markmullen · 08 June 2015, 21:50

We use a Mercury 60 4 stroke (2004 EFI model) on a 5.3m Humber as a patrolling rescue boat. The engine is lovely and quiet (quite important as we are operating in the city centre with lots of riverside properties, at night) and very very economical. With 3 big lads and some medical kit on board it'll do 24 knots comfortably.

buzz · 09 June 2015, 17:25

Quote:

Originally Posted by markmullen

We use a Mercury 60 4 stroke (2004 EFI model) on a 5.3m Humber as a patrolling rescue boat. The engine is lovely and quiet (quite important as we are operating in the city centre with lots of riverside properties, at night) and very very economical. With 3 big lads and some medical kit on board it'll do 24 knots comfortably.

Thanks for the info on your 60 4 stroke and its performance with 3 big lads aboard. Do you use it just on the river or do you also use it on the sea. Would be Interested in how it would perform in a bit of a chop.

markmullen · 09 June 2015, 17:27

We're river based so haven't had that one out to sea I am afraid.

Last Tango · 09 June 2015, 18:54

The performance of the 75 two stroke will be significantly better than the 60 four stroke if that's important

and the reliability of a gearbox will have more to do with how it's been driven and maintained. As far as I know the gearbox on my Honda BF130 came from that 75HP Mercury. Over the years I've had a couple of gearbox failures, but never Mercury or Mercruiser.

I take it the way you know your Yamaha has the gasket problem is when there's a smell of hot metal and steam and smoke coming from places it shouldn't be

Festinghouse · 09 June 2015, 22:18

seems a bit harsh to me. the 75 and 90's are great engines - they love to rev, are are easy to work on. the one piece block means no head gasket to fail, though to be fair that also causes a problem should the block need a rebore. the early black stators did fail (though mine is still fine)the red ones are way better. ive never heard of the gearboxes being weak, but any failure is likely to be caused by operator failure - ie being slow to engage gear, chewing up gears.

Quote:

Originally Posted by phantom 19

The Mercury 75hp two stroke is a massive lump of an engine, a detuned 90hp which was already heavy for its class. It is also not the greatest engine with usual Mercury issues with the stator which will fail at some point, shonky lower shock mount castings, one piece block and head casting etc. gearboxes seem weak too, there is a ready market for second hand good gearboxes. The Yamaha 75/90 was/is infinitely better.

The mariner 60 fourstroke is a Yamaha powerhead that Mercury/mariner bought in and in their wisdom mated it to one of their own legs / gearboxes. They got the leg water pipe sealing arrangement wrong and used a iffy rubber seal which over time deteriorates and actually blocks the water pipe up. Resulting in having to lift the head and strip the leg down to component pieces to rectify. Otherwise it is a good powerhead although dated now with four carbs etc which if DIY fiddled with need setting up properly again.

freespirit3 · 09 June 2015, 22:28

Quote:

Originally Posted by buzz

Thanks for the info on your 60 4 stroke and its performance with 3 big lads aboard. Do you use it just on the river or do you also use it on the sea. Would be Interested in how it would perform in a bit of a chop.

Not sure but I think the 75 2t is about the same weight as the 60 4t and on a humber assault I think the lighter engine will suit the hull better.

We had a 70 2 stroke Tohatsu on a 5m assault and it was just right, I always wanted either a 75 or 90 2t mercury just for that bit extra.

The early 4 stroke mercury's are huge engines and look really heavy, I am sure if they have both been looked after they will both be good, for turn of speed nd pure fun I would go with the 2 stroke, best of luck, great boat