OMC 3.0 L Replacement

[saywhat]

I have a 160 Four Winns with an OMC 3.0L Cobra, and Cobra outdrive I picke up for very short money as a project. And what a project it is.

The block is junk as the previous owner stored it outside during the winter and didn't drain it.

I am mechanically inclined and have access to a garage facility - but I'm certainly no boat mechanic.

Here are my options:

1. I can get a reman shork block and replace that portion.

2. I can get a complete low time (250 hr) used 3.0L locally for about 1K

3. I can get a recently rebuilt 4.3 Merc and outdrive locally from someone i know for about 1K

My concern is the Cobra outdrive that's on the boat and the condition - especially if the engine was not taken care of properly. It looks okay and works, but...

Would a larger mercruiser and outdrive fit on the boat?? Where could I find that info.

Thanks in advance for any insight you can provide.

 

[andy1canada]

Re: OMC 3.0 L Replacement

Howdy from Canada!

Welcome to iboats!

You'll find lots of good help here from (unlike me) 'qualified' people... but I'll dive in anyway.

First off, where will you be using the boat? If you are running in the salt-chuck - and your boat is indeed a 16-footer - I'd lean towards a lighter package to maintain as much freeboard as possible to keep it half-way seaworthy. If you drop a V-6/Merc in her, you'll be planting almost 900/lbs in her stern and even if you are going to be running in lakes (flatter waters) you'll likely need to counter-balance the engine weight with a sizeable bow-tank to balance her out, if it doesn't have one already (more-$$$$).

If it was mine, and the stringers and transome were still reasonably solid (you need to determine this), I'd turf the OMC (part it out to recover what you can) then re-power with a 'NEW' Volvo or Merc 4/cyl sterndrive. They're not cheap but with that comes a warranty, and piece-of-mind that you'll be getting you and yours home again at the end of the day.

I've been down the used-rebuilt-low/hours-cheap/cheap-great deal! road before and have learned the hard way. Being towed-in can be somewhat embarassing.

Good Luck!

Cheers,
Terry

 

[whywhyzed]

Re: OMC 3.0 L Replacement

2. I can get a complete low time (250 hr) used 3.0L locally for about 1K

Is that with carb and manifold and everything?
Your 3.0's manifold will likely be toast too if the block is cracked.
Of the options you gave, pending compression test and visual inspect, I would think #2 is probably the best deal. And the fastest for getting you back out. Especially if it's a dressed engine. 250 hours is actually not that super low for a boat engine. 35 per year is the average around my area. But if well maintained, you can get many years service out of it.

The V6 Merc thing is only feasible if the whole boat comes with it - transom plate, steering, trim system... wiring and dash controls for trim...everything.... then pending measurements and stuff, it's doable, but a fairly serious project. The Merc transom cutout IS the same as Cobra though.
Without a donor boat, you'll be doing a lot of Merc-OMC connecting and converting for which there are no manuals....again all doable, but labour intensive and skills required...need to be good with electrical

Going from a 4 banger to a V6 only adds around 200 pounds -equivalent of 1 extra person standing at the back of the boat. If you weigh 200#, Go sit on the engine cover - that's how it'll sit.
Did 4-V6 conversion in my 17 footer - only sits an inch lower in the back judging by the waterline on the hull.

 

[saywhat]

Re: OMC 3.0 L Replacement

First, let me say thanks for all the responses thus far.

I will say that I am hesitant about repowering with a merc - although it would be coming from a donor boat with all associated wiring, plumbing, etc. - Sounds more like a winter project - plus I don't like the weight issue on such a small boat.

The used motor is a decent deal. It is a complete motor + manifolds + accessories, but once again, it's a used motor.

If it was anything but the block (manifold, head gasket, cracked head) I would feel a bit better about everything.

But the old saying is correct - the less you spend on the boat, the more it will cost you in the long run.

I guess I have some decisions to make. Thanks, again, to all!

 

[4winnsskipper]

Re: OMC 3.0 L Replacement

First, let me say thanks for all the responses thus far.

I will say that I am hesitant about repowering with a merc - although it would be coming from a donor boat with all associated wiring, plumbing, etc. - Sounds more like a winter project - plus I don't like the weight issue on such a small boat.

The used motor is a decent deal. It is a complete motor + manifolds + accessories, but once again, it's a used motor.

If it was anything but the block (manifold, head gasket, cracked head) I would feel a bit better about everything.

But the old saying is correct - the less you spend on the boat, the more it will cost you in the long run.

I guess I have some decisions to make. Thanks, again, to all!

an inline 4 on a 17 foot boat is plenty. unless you need to hit 50+ go v6, otherwise my inline 4 has pushed my four winns 17 foot to 41 mph, with a clogged exhaust and 22 pitch prop...i've now unclogged the exhaust (burnt up exhaustr flapper blocking the exhaust exit on the sterndrive and hope to hit atleast 45 mph, and thats pretty good in my book, especially for an inland boat. your best bet is another 3.0L. not to mention using less gas, which is a BIG plus with the gas prices these days