Mariner Outboard - Never Again

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KeelsonGraham

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My 3.5hp 4-stroke has packed up after 3 seasons (this would never happen with a Tohatsu). It’s probably something simple but how to tell. Mariner don’t publish manuals online, you have to buy a paper version. It’s 2024 FFS, not 1980. I will avoid this brand like the plague from now on.
 
KeelsonGraham said:
My 3.5hp 4-stroke has packed up after 3 seasons (this would never happen with a Tohatsu). It’s probably something simple but how to tell. Mariner don’t publish manuals online, you have to buy a paper version. It’s 2024 FFS, not 1980. I will avoid this brand like the plague from now on.
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Can I pop round and collect it before you take it to the tip?
 
We have a Suzuki 4HP from 2007. It has never missed a beat in our ownership, nine seasons so far.

I ALWAYS run it after turning the fuel tap off until it stops. Restarting just requires two or three pulls, leave thirty seconds and then pull choke on and start. Always starts second pull. The initial pulls get a vaccuum going to pull the fuel to the carb.

I always drain the carb over winter.

I dont know for sure, but modern fuel evaporates and turns so 'gummy' it blocks the cold start and idle passages, especially on small 4 strokes.

Which is why the above is so important.

Good luck getting it fixed, I hope it is as simple as I have described to make it reliable.
 
I now add an enzyme fuel treatment (startron by star brite) to the petrol for my engines. 2nd year of doing it. Seemed to help the malta that started on the 3rd pull after a year sitting in a locker.
 
A very possible cause is the carburetor, problems caused by the ethanol, espcially with the E10 grade.
The ethanol in the fuel binds water over time and can cause corrosion in the fuel system.

Just had a recent experience with this, and found the needle valve had this greenish gunk on it. This was causing the needle to stick and not seat properly leading to the carb flooding.
Cleaned the needle and that solved the issue, but I did note that the needle was pitted so purchased and fitted a new part.

In the past I used to close the fuel valve and run engine until it stopped if the engine was not going to be used for any length of time, but now as well as this, I remove the drain plug and drain out the last of the dregs of fuel (also use Sta-Bil Ethanol Treatment and Stabiliser)
 
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I've often read a lot of outboard/lawnmower/etc issues are to do with the gummy residue left behind in the carburettor when petrol evaporates.

Draining the carb seems to be the easiest precaution against this. A lot of o/bs have a carb drain plug for this purpose. Only takes a minute at the end of your boat trip (when your cold/wet/tired or in a hurry to catch last orders) :)
 
I bought my Tohatsu 3.5 HP in 2004 in Alderney (tax free). Other than the occasional reluctance to start that is the curse of 2-strokes it has performed faultlessly. Definitely a worthwhile purchase. It replaced a relatively new Mariner that gave endless trouble
 
fredrussell said:
Small petrol outboards are the work of the devil.
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If you say so. But our Mercury/Mariner/Tohatso 2 strokes from last century are light weight, simple and very reliable if fed recent E5 petrol and carb kept clean. If feel like over doing the love change the spark plug every 5 years or so, Cheap and simple.
 
A big problem with Tohatsu built 2.5/ 3.5 fpur stroke models ( Mercury, Mariner, Evinrude ) is that the cam timing gear is bonded to the crank.
Sometimes especially with rebuilt powerheads the timing gear slips on the cranl and throws the timing out.
Im trialling some new bond that apparently will work, unforfunately due to tolerances welding the gear on isnt viable
 
Steve65 said:
A big problem with Tohatsu built 2.5/ 3.5 fpur stroke models ( Mercury, Mariner, Evinrude ) is that the cam timing gear is bonded to the crank.
Sometimes especially with rebuilt powerheads the timing gear slips on the cranl and throws the timing out.
Im trialling some new bond that apparently will work, unforfunately due to tolerances welding the gear on isnt viable
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That's interesting Steve. Does it extend to the 4hp and up models? Local friend needs one to replace his 3.5 4T Mercury. Works fine, but probably will sell with the boat, so needs another, pref with reverse, for his newly finished bigger project.
 
I havent encountered an issue in any other outboard..I know its an issue on some landrovers, Competition land rovers have the gear welded on
 
Steve65 said:
I havent encountered an issue in any other outboard..I know its an issue on some landrovers, Competition land rovers have the gear welded on
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Cam belt crank pulley on my Renault is held only by friction... no key. But, held on with a single use bolt that is REALLY torqued up. 89ft/lb + a further 90°.
 
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