Replace Mariner 30 2S with Bigger Motor

[MountieMike]

I bought a 20 year old Zodiac 420 Yachtline last year. The tubes are excellent, the whole rig is in good condition in fact. I feel the motor (a Mariner 30 2St which I'm guessing to be original) feels a bit underpowered and tired. I am considering swapping for a 4St with a bit more HP. Zodiac's maximum recommended HP is 40, so I'm considering a new Honda BF40 with PTT (currently no PTT). I realise that's going to weigh more, which counters some of the increase in HP.

Does anyone have any advice on my situation? On the Honda BF40?

Thanks,

Mike

[spartacus]

I'm sure the Mariner 30hp 2-stroke is feeling tired. The good news is there's still a market for 2-strokes, regardless of condition if you sell on Ebay or Gumtree. What you lose in hole-shot you're likely to make up for with electronic fuel injection, better fuel consumption and reduced decibels while underway!

Any reason it has to be Honda? If you're opting for a mid-power 40hp, you have all the big names. Couple of things to weigh up is dealer-location. Any warranty is tied to regular service intervals, so that's one thing to consider if you need to visit annually.

Also weight, 4-strokes can feel significantly different on a small RIB, especially as you've been used to 50kg hanging off the transom.

Honda BF40 (LRTU or LRTZ) - 98kg
Tohatsu MFS40A (EPTL) - 95kg
Suzuki DF40ATL - 104kg
Yamaha F40 FETL - 98kg
Mariner F40 ELPT EFI - 98kg
Mercury F40 EFI - 98kg
Selva 40 EFI - 99kg

Pretty sure Mercury/Mariner is the same engine. I'm sure someone will correct me if that's not the case. I also know nowt about Selva - but added into the mix anyway.

Be interesting to see what Called42 did? He posted this last year.
https://www.rib.net/forum/f8/zodiac-...ket-85566.html

[MountieMike]

Thanks for that; most informative. Why Honda? Well I suppose reputation generally, also I've had a Honda generator for a couple of years now that runs like a watch (only a bit louder) and in a conversation with a yard owner on Anglesey he recommended them.

I had to look up what hole-shot means :-)

[9D280]

To add to what Spartacus said - Some of the older ribs werenlt designed to take the heavy weights of the modern 4- strokes.

Check the max weight capacity of your transom...

Mine (early 80s vintage when most engines were premix 2 cyl) and It maxes out at 50 KG... Try finding a 50KG 60Hp engine these days!

Most engine assemblies share with a couple of other Horsepower ratings, so , for example, the ols Suz 25Hp 3 cyl was a realtively simple carb change to make it into a 30... (so the 25 was quite heavy compared to , say the Evenrude where the 25 was the same lump of engine as the 20... (Does that make sense)

Having said all that, 20YO makes the hull round about the Y2K mark or so, when 4- strokes were beginning to appear, so this may not be as big a problem as it might seem...


I've only got a 2005 brochunre, but FWIW, the Yachtline Delux 420 of that year says 120Kg / 50 HP max engine weight, so hopefully that should be enough (But check your specific model!)

[MountieMike]

Thanks for that. Your figure for max transom weight is close to my figure: 115Kg. The manual I have (for Zodiac 420 Pro) says max recommended HP is 40 but absolute maximum of 50.

[Blankton]

Is an extra 50kg in weight worth it for an extra 10HP? I suspect that due to the extra 50Kg hanging off the back of the transom, there would be negligible performance increase, maybe a slightly higher top end, but slower acceleration.

You could give your 2 stroke a bit of a health check - compression test, carb clean. If thats all good, then I dont see why it would be low on power, just because its old.

If you do go for 4 stroke, I think the hondas have a common fault where they get a fatigue crack in the gearbox casting.

[MountieMike]

Yes this is the nub of my question really. Also Anglesey is one of the places we'll use the boat and a local yard owner (not trying to sell me an engine :-) described the engine as the weak link in the setup and that reliability is paramount in waters like those around the island. Though unreliability is never an attractive option I guess!

I thought about this and checked the weight of the BF40 and the BF50. I'm guessing this is often the case: they seem to be the same engine. So I may opt for the 50, which is the maximum HP the boat is rated for.

Thanks for the info on the Honda gearbox casing.

[Pikey Dave]

Originally Posted by MountieMike

Yes this is the nub of my question really. Also Anglesey is one of the places we'll use the boat and a local yard owner (not trying to sell me an engine :-) described the engine as the weak link in the setup and that reliability is paramount in waters like those around the island. Though unreliability is never an attractive option I guess!

I thought about this and checked the weight of the BF40 and the BF50. I'm guessing this is often the case: they seem to be the same engine. So I may opt for the 50, which is the maximum HP the boat is rated for.

Thanks for the info on the Honda gearbox casing.

Personally I’m not a Honda fan, but each to their own. Have you spoken to the guys a Dulas Boats on Anglesey? They are now my “goto” suppliers for all things outboard. Very helpful & knowledgeable and competitively priced. I think they sell several marques.

[Blankton]

Look at the locals boats in the harbour. I bet you'll see as many (if not more) 2 strokes than heavy, complicated 4 strokes.

There is no reason a 2 stroke can't be reliable - the RNLI use enough of them! Obviously if your engine is actually breaking down / not starting / heavily corroded then that's a different matter. But so far the only negative I've heard, is that one bloke didn't like the look of it....

[Pikey Dave]

Originally Posted by Pikey Dave

Personally I’m not a Honda fan, but each to their own. Have you spoken to the guys a Dulas Boats on Anglesey? They are now my “goto” suppliers for all things outboard. Very helpful & knowledgeable and competitively priced. I think they sell several marques.

https://dulasboats.co.uk/