mariner 125 hp 2 STROKE

[simon23]

What do you think of the mariner 125 hp 2 STROKE pre optimax
It's a 2002 model and I want to put it on a 6.1 meter tohatsu one design

[jambo]

Originally Posted by simon23

What do you think of the mariner 125 hp 2 STROKE pre optimax It's a 2002 model and I want to put it on a 6.1 meter tohatsu one design

Well I've got a 1997 150hp V6 and won't change it. Wot what a sound and grunt you'll love it!!

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[Festinghouse]

go for it! you giving up on the tohatsu?

[uncle al]

That should be the 2+2 system on it , not very good for water skiing.

[Boats&Outboards]

They are awful!

Its a 4 cylinder model, which runs on 2 cylinders up to around 2,000 rpm, then the full power kicks in. This makes them lumpy at tickover and also they are quite difficult to control coming into berths etc as if your on that threshold of revs and need a bit more to bring her in (thus going over the 2,000rpm range) you suddenly get a whole heap of power.

It was a model not built for long. The the same with the 4cylinder 115, you get used to them but not a lot of people like them. Some people had concerns on how the cylinders get oiled when running on 2, although I don't think its a problem.

The benefit is they are a bit more frugal on fuel at tickover and once your used to controlling the power are smoother midrange engines.

www.BoatsandOutboards4Sale.co.uk

[uncle al]

Boats&Outboards, you got it in one, I tried to say it a bit more gently. I must be getting old.

[jambo]

Well you learn something everyday on here. That's the reason it's such a good forum.

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[Jeff]

I had the same motor on my first RIB - as the wizzos on here have said, its a very abrubt jump from 2 to 4, quite weird to handle and a pain in speed restricted areas.
I had trouble with freezing carbs in the winter trips to Tobermory (solved by the addition of a mercury 'cold weather kit' ---- a small selection of pipes and tees to route water round the carbs I recollect)
The bottom carb also seemed to attract salt(water) and give issues and I really dont think the 2+2 made any great difference on economy. Quite a thirsty beast and temperamental to start /flood compared to the newer outboards. Swapped it for an Opti
I wouldnt opt for one unless its the best/only option you have
The one 'advantage' is of course - 'simple' to work on with no electronics
Jeff

[Festinghouse]

id never heard of this 2+2 system, it does sound a bit crap! my force 120 is as basic and crude as a wheelbarrow, but has some real grunt behind it as well as being controllable at low speed.

[uncle al]

Force was a brand name from mercury its a commercial obm , (supposed to be easy to repair)

[Boats&Outboards]

Originally Posted by uncle al

Force was a brand name from mercury its a commercial obm , (supposed to be easy to repair)

I thought Force was always a brand they never wanted, ie it came with US Marine/Chrysler when Brunswick bought Bayliner and they ditched it as soon as they could. Was it really there commercial option at the time ?

www.BoatsandOutboards4Sale.co.uk

[ribsta]

I bought one of these Merc/Mariner 125hp brand new in 1998 for my Ocean 6.25. It ran terribly. After complaining to Sowester (dealers in Poole at the time) Barrus agreed to swap the engine outright completely free of charge for a 135 V6. This included installation, the lot. They must have known even at that time these engines were problematic. The 135 was a dream, could not believe why I didn't chose that in the first place.

[uncle al]

BoatsandOutboards, the factory in Belgium regarded the force brand as comercial. Your correct in writing its a crysler, I know I used to dread working on them, so I didnt work on many (we had lots of very nice dealers)
ribsta, I would probaly (likely) worked on your 125 obm when/if it got back to bare arse.for re-sale to a dealer, because I used to run them in the test tank,sevice them and them winterize them for resale.

[simon23]

Thanks for all your input . I'm in a quandary now. Can't afford a optimax. Had a grim season last year with 90hp tohatsu seamed to be problem after problem. At just over 2 grand seemed like extra power and a fresh start may be worth another trip to the engineer with the tohatsu

[Festinghouse]

force - chrysler block etc but with mercury ignition, electrics and gearbox. much more basic than my mariner 75!

[ribsta]

Originally Posted by simon23

Thanks for all your input . I'm in a quandary now. Can't afford a optimax. Had a grim season last year with 90hp tohatsu seamed to be problem after problem. At just over 2 grand seemed like extra power and a fresh start may be worth another trip to the engineer with the tohatsu

Why not look for a decent 2nd hand 2 stroke Yammie 90?

[simon23]

Had a yammie 80 auto lube on the my last rib was great till it blue a piston. The extra hp sort of helped to justify the expenditure.

[steve-ribnet]

Just my observations as an owner of a 2+2 mariner 100hp carb 2 stroke, and past owner of both a 90 carbed yam and 115 optimax

Tickover is not lumpy at all- no better or worse than the yam

Stooging around harbour speeds is no issue at all - the transition to 4 cyls is way outside harbour throttle ranges.

There is a marked lurch on passing the throttle threshold for the other 2 cyls to open up when gunning it, which I admit can be uncomfortable for the uninitiated. Some people like the acceleration! It is fine for leisure skiing/towing etc as long as your boost pump and associated plumbing is working fine and you give it full bifters; the transition is then fine at least for amateurs like me.

If you increase throttle v.slowly then then 'boost' pump that aids transition from 2 to 4 has little effect and it can sound rough ( it is like a plunger pump that is pushed by the throttle arm).

I use the boat for diving so spend long times stooging around. In theory this would save fuel but surely it is insignificant compared with WOT fuel rates?

Oiling of the 2 non-idle cranks and rods still takes place via crankcase as usual. Theoretically the upper ring may get less oiling??? Engine is 1996 and no noticeable problems in this respect ( touch wood)

Would I buy an hpdi to replace it? I value reliability and at-sea maintenance over fuel economy, so no. We had many more issues with electronics on the opti.

[steve-ribnet]

Ps
I loved the 90 yam carbed 2 stroke. If this 2+2 died and funds were tight I'd look for another yam 90 to replace it

[simon23]

You're not helping my quandary
Lol