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Repower contemplation

wynjim55

wynjim55

Regular Contributor
I am currently pushing my old late '70s 15'/4.5m fibreglass half cabin boat with the original 55hp 2 cylinder 1978 Mariner it was fitted with from new (only got this outfit last year). I am considering re-powering to a more modern outboard but am unsure which way to go. We (3 kids, wife, and I - total roughly 600lb/275kg) use the boat mostly for fishing in the sheltered saltwater bay near home, the kids are also keen to use the tube they got given for Christmas by a family member. We haven't considered water skiing but who knows in the future, I'm thinking this is the wrong style of boat for it. There is a freshwater lake within about an hours drive but regulations only allow outboards up to 60hp with a rating of 2 or 3 stars. The boat from memory is rated to 75hp max (rated in the late 70s). I would like to stick with electric start and hydraulic tilt/trim.
Crest Craft.jpg
Should I be looking to go 4 stroke or stick with 2 stroke? Are there any makes/models which would suit my type of usage more so than others? Should I forget going to the close lake and stick with others not so restricted? Should I be looking at outboards with a rating closer to the max for this boat? Where do I start. Locally there are dealers for Mariner, Mercury, Honda, Evinrude, Yamaha, Suzuki. I have had good service from the local Yamaha dealer (general boat accessories and parts for the current outboard as it is Yamaha built, Mariner badged, Mercury marketed). Any suggestions gratefully received.
 
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E-tec were recommended to me also but coming from only one source I was looking to see what others thought on this topic. E-tecs are a 2 stroke unit but operate completely differently to old school 2 stroke units. I believe Honda only build 4 stroke outboards.
 
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E-tec engines are extremely fuel efficient 2 stroke engines on par w/fuel efficient four stroke engines w/more low end power and less weight.
 
Over their service life a 4 stroke will generally cost you more in maintenance - assuming you have to use a dealer.

If you were looking at a 75 horse you do have a number of options -

4 strokes - take your pick, but as noted, Honda is outstanding - one note on Honda, when they discontinue a model they also discontinue parts support. Talk to some owners of "older" Honda's and they can tell you. After a certain age, if something major goes you end up with a paperweight if you can't find (limited) parts in the used market. Unlike an old Merc/OMC where there are thousands in the market place, Honda is a small player.

All else being equal, a direct injected 2 stroke is every bit as quiet, fuel efficient and "clean" as a 4 stroke and it often sells at lower price on a "dollars per horse" comparison.

In the 2 stroke (Direct Injected) market you have BRP (Etec) and Merc (Optimax), both in 75 horse and Tohatsu (TLDI 70 horse).

The ETEC's use very high pressure direct injectors and their long term durability is still not known. Both Merc and Tohatsu use low pressure injectors (jointly developed technology).

This is just my opinion but it seems to me an injector handling pressures of upwards of 1000 psi is going to blow it's cookies before injectors only dealing with 120'ish psi over the longer term. But that in itself would not stop me from buying an ETEC.

If you have service support I would suggest you look at Tohatsu - they are lower cost but yet quality built (Tohatsu builds all the "under 40 horse" Mercs, plus all the Nissans out there).

If service is scarce, stick with the brand "most popular" in your area.

One final note - pushing weight cost's gas.

Tohatsu 70 TLDI - 315 lbs
Merc 75 Optimax - 375 lbs
BRP 75 ETEC - 320 lbs

Merc 75 4 stroke - 399 lbs
Yami 75 4 stroke - 369 lbs
Honda 75 4 stroke - 359 lbs
 
In addition to the EFI maintenance, the 4 strokes have valves that can need adjustment, and timing belts that need changing.

Jeff
 
I checked and there is also a Tohatsu dealer in town.

It's been a while since I played with 4 stroke motorcycles (street bikes) but it is coming back to me. It really has been a long time.
 
Sorry, I had forgotton about a recent yamaha addition to their line-up (came out a couple of years back maybe).

They have a (very) lightweight 70 horse 4 stroke option. Tipping the scales at about 260 pounds and retailing in the low 7K pricerange (if you do some looking).

It is light on the cubic inches (about 60) compared to it's bigger brother, the 75 (with 97 cubes) which would tend to reduce it's lifespan (compared to most 75 horse models built on the 90 horse powerheads) but the gas savings alone for pushing upwards of 100 pounds less every time you go out might well make up for the shorter service life if you did a cost analysis over it's lifetime.

Of course, you still have the service requirements of a 4 stroke - but Yami does build more outboards than all other mfg's "combined", so at least you can trust that you would be getting a decent product. And Yami's are serviced just about everywhere...
 
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