Mercury f90 four stroke

benjamin · 21 November 2002, 13:01

I am off this w/end to trial a 2nd hand (1999) Ribcraft 585 fitted with a 2 year-old (2000) Mercury F90. This is the boat on which, after much research, I have set my heart, but my 'dream ticket' motor was always a Yamaha f100.
I know nothing about the Mercury f90 motor in particular, but have not heard great things about Mercury in general (reliability problems?) I have read that the 'Power head' of the Mercury is identical to the Yam f100 (Pardon my ignorance - what does that mean? is it everything above the drive leg or is it only the cylinder head?)
If anyone has knowledge of this engine - good / bad or indifferent, I am grateful for any input as this is going to be a serious investment for me & my family!
Secondly, is 90hp on this boat appropriate for family (2 adult, 2 children) boating in Solent and around S Coast with occasional donut / wakeboard afternoons planned?

Any thoughts / comments, Please

Tiger · 21 November 2002, 13:14

Good hull, and a fair amount of power for that size of boat.
Sould be fine for towing, if a little fast (you dont have to use all the power though).
Can't comment on the engine.
Tiger

John Kennett · 21 November 2002, 13:27

I'll second Tiger's comments!

It's a cracking boat, and 90hp is a good size engine to have on it for all round use. I don't know anything about the Mercury F90 either though . . .

I reckon you'll have a lot of fun with this boat.

John

Alan · 21 November 2002, 14:51

Good boat as other say. I believe Jools has this combo so try asking him for his thoughts?

benjamin · 21 November 2002, 15:31

Thanks Alan,...Have already left a personal message to Jools and drooled over the photos of his very smart and much newer outfit!

dgpw · 21 November 2002, 16:50

Hi the boat is great . The merc 90 f stroke is a good engine. It provides a steady amount of power up until just under flat stick and will be perfectly suited to the boat. I believe that the boat is speced for up to a 115 or 120 but as the merc is a 4 stroke and heaver it will be about perfect. I have only used the 90 half a dozen times but have had no problems it is economical and provides good power. I have used the merc 75 alot and that is a great block never fails and provides loads more power than a Honda 75. Merc sell their legs to Honda who spray them silver. Hope that is of some help.

Dave Clarkson · 21 November 2002, 17:55

I have this exact set-up, bought a year ago, then one year old. I have used the boat on a couple of cruises with Biboa (last one a one way trip to Weymouth!) and several "solo" trips including across to the Scilly's, 2 adults, 2 "kids" plus luggage for 4 for a fortnight. It's a great all rounder, economical, quiet, safe, reasonable speed (25 knots cruise is comfortable), pulls skiers no problem and is just big enough, and well made enough, to take some serious weather. Ask all the ribbers and they all wish for a little more length (no offence lads

), but that's irrespective of whether the've got 5.85m or 9m!! As for the engine, I can't compare to the Yam but mine's performed faultlessly. We've had a great first year's ribbing in this boat and I have no hesitation in recommending it to you. If I can be of any further help, please send a PM.
Regards,
Dave

benjamin · 21 November 2002, 19:30

Thanks to all for a fantastic and encouraging response - are there any 'professional' (training schools etc. ) Mercury f90 users out there with experience of really hard / prolonged use and abuse of this engine?
The boat is a distinctive blue / orange colour, called 'Pilchard' - anyone come across her in / around the Solent?

LURCHER · 21 November 2002, 19:40

I ahve a 5.85 with 115 Evinrude Ficht which I abuse dreadfully and am always feeling guilty about how I treat it and the engine . Both behave faultlessly and are not nannied in any way . Power is about right I had a 100 merc at first but changed to the 115 .Drop me an E mail if I can be of any help .
John

wavelength · 21 November 2002, 19:51

Well I'll put the cat amongst the pigeons then. We bought a new f90 merc with our humber new in 2001. It seized solid in poole harbour entrance when the oil pump seal went 3 weeks after purchase. Humbers were great but sowesters were struggling and soon after went into receivership. They replaced the engine within days but only after pressure from humbers and myself. The replacement engine seemed fine but the paperwork for it was not and I was far from happy. To Barrus's (and Humbers who pushed the action along) enduring credit they sorted a replacement to the replacement soon after they took over the agency and with proper paperwork.
Apparently all sorts of recalls followed the incident. the replacement mercs have been totally reliable, quite, smooth, economical and a pleasure to run. Our boats are in regular use and everyone loves the Merc. But that first incident still lurks somewhere in the recesses of the mind. Something about being between a rock and a hard place - to be precise the seacat, the chain ferry, and a strong onshore wind. The benefits of an experienced crew saved the day but I could have done without it-oil and petrol all over my nice new boat!

Keith Hart · 21 November 2002, 20:08

Dave

Next time you are in trouble, fill the boat with water and await rescue.

Keith (sorry Alan P ) Hart

Jono Garton · 21 November 2002, 20:24

Hi All

I run a merc 90f on a Avon Adventure 5.6m. Had a few problems -

Fixtures broke on engine lid. Fixed under warranty

Engine missing on a cold start. Fixed under warranty

All in all good powerfull engine on the Avon and having driven wavlengths Humber "dito".

Would prefer yam f100

wavelength · 21 November 2002, 22:50

Had to put shedloads of fairy liquid in with the water to shift the oil keith! Left a trail of bubbles out thru the drainer first trip afterwards Pity I couldn't get the b****r in the dishwasher!
Seriously though that was one catastrophic machinery failure I could have done without but I suppose there is always one rogue one no matter what the product, I just wish I could avoid buying 'em - but the replacements have been no trouble whatsoever in any way at all - turn the key, starts first crack and it never misses a beat - now a statement like that is surely courting trouble

dgpw · 22 November 2002, 10:32

As I am sure u all know. An engines quality mainly shows up in the first 100 hours or so. Same with car. If you get to 100 hours with no problems then the chances are that with regular servicing and care the engine will run for ever. Any of the manufacturers have bad eggs unfortunate to get one but never the less possible. If the merc has been running fine for a year then with good servicing you should have very few problems.

benjamin · 22 November 2002, 12:02

DGPW, - If I have read your profile correctly, that is sound advice coming from someone with responsibility for 40 4- stroke outboards - this seems a staggering number, or should I read rather one 40hp 4 stroke outboard?

dgpw · 22 November 2002, 15:32

That would be several 40 4 strokes not 40 of them infact prob only 4 or 5 I will change it

benjamin · 24 June 2008, 11:38

I have just re-read this thread which I initiated back in 2002 - my Ribcraft 5.85 / Mercury f90 combo has given the family 5 seasons of wonderful rib-bing, in the Solent, to the beach and back, wakeboarding etc. and has now moved to Cornwall. Sadly, the engine has now been declared scrap owing to corrosion in the power head, possibly attributable to a metal gasket between the Mercury leg and the Yamaha - sourced powerhead. Metal between the oil and water channels is now below 1/16 in. - anyone else had this problem with this motor? (it is a 2000 model - dead after 7 seasons, in spite of regular flushing out with fresh etc.....
Looks as if I shall have to buy the Yam f100 I originally dreamed of, after all - anyone know of any 'cheap' ones out there?

wavelength · 08 July 2008, 11:34

similarly we still have our merc 90/ocean pro set up. we have had and still have other boats of course but kept this one as the kids considered it their own, except when it needs work doing on it of course! Doesnt get much use these days as they are working away but has develeoped a misfire now and it seems it is down to one of the triggers which come new as a package with the stator and are ******* expensive. Failing that it is the CDI unit. So the question is has anyone got said parts from an otherwise dead engine ? Are parts available from yours Benjamin?? or does anyone know of someone breaking one of these for bits?

Cypman · 08 July 2008, 17:48

We had a Mercury F90 on a 5m Humber Destroyer. After 3 years busy use as a club rescue and training boat (not sure of total hours but probably circa 500 and regularly serviced) it developed an oil leak at the head/leg joint. On stripdown, it was discovered that the internal corrosion was severe, indeed, there were holes in the crankcase and the engine was considered to be beyond economical repair. After a review of our routine we determined that daily flushing was typically less than 2 minutes and allied to the increaed salinity of the Eastern Mediterranean was insufficient to remove the salt. Since increasing the flushing time to 5 minutes we have had no problems with the replacement and another engine (Suzukis). Am still unsure as to whether corosion was the sole cause of the engine failure though!!!

wavelength · 13 July 2008, 19:37

oh bliss. it wasn't the expensive CDI unit or the even more expensive triggers and stator assembly - it was the interupter switch setting on the gear linkage. The switch drops the engine down to 2 cylinders from 4 when moving out of neutral to lessen the shock load on the gearbox. Only mine was forgetting to put it back to 4 cylinders again! Bit of adjustment, and a tune up at the same time, and its running fine

in fact better than it has for a long long time! Which is a bold statement I hope I don't come to regret.