1969 Crestliner Norseman 120 OMC Repower???

Hey Everyone,

I just joined this forum because I recently purchased a 1969 19’ Crestliner Norseman with an OMC 120. It has a welded aluminum hull, a cuddy cabin with windshield and side windows, and the original shoreline tandem axel trailer. I paid $350 for the set up and I am excited to get on the water, but I’ve got some work to do.

How We Will Use the Boat
My family will use the boat to lake fish, pull tubes and the occasional boarder, and maybe do some lake camping (Yellowstone, Powell)

The Work We Are Planning
The boat has sat without running for as much as 40 years (original owner passed away 2 years after buying the boat new--125 hours on the boat) and I believe it has sat ever since.

The second owner (purchased in the 90’s) made an effort to get it running but decided he did not have the wherewithal. He left it sitting with the carburetors off and one spark plug out. With that in mind, I intend to go through the motor (new gaskets, seals, bearings, rings, honing?, etc.); then there is a bit of engine electrical to be reworked (thanks to the second owner also); and carburetors to rebuild/replace (dual carb set up (benefits/disadvantages???).

We Are Considering a Power Upgrade
Since the motor needs to be gone through, carbs are in pieces, and the engine electrical will need to be reworked, I am considering purchasing a larger power plant that is in running condition. My aim would be to purchase a complete used unit to install; or purchase a donor boat with a running motor.

Here are some key variables you may need to know.

• Current setup weighs 1325 lbs dry
• Boat is rated to carry 8 people and 2410 lbs of people and cargo, we will probably do that!
• I’d love to pull multi-person tubes or even a big banana tube if possible so I can involve multiple family members at the same time.
• I want to be able shake riders if possible, not take them for a Sunday stroll! Those teenage boys and their friends need to feel the love!
• I want the set up to be reasonably stout and dependable. I can maintain it and repair it if needed, but who wants to spend their time fixing it. We want to be on the water!

Question 1
Is 120 hp going to be adequate for the boat and our intended uses, or will additional power be needed/desirable? Note: I am trying to be practical here. I think most people want more power!



If more power is needed/desirable...

Question 2
How much power should I be looking for? (I believe the OMC 800 I have was used with up to 235 hp)

Question 3
Any difference in what will be needed to mount a larger motor to my ‘69 OMC 800 or the boat? Outdrive Gears (upper unit)? Mounts?

Questions 4
Will additional power create additional issues with the stern drive?

Question 5
I have three props, all 14”. I have a 14, a 15, and a 20 pitch. Will I need to purchase additional props?

Question 6
I’ve got access to a ‘76 OMC 175 (I believe that’s the Ford 302). How would that be?

Ayuh,.... In all honesty, unless ya up-grade to a Mercruiser or Volvo drive at this point,....

yer spinnin' yer wheels, 'n goin' Nowhere.....

That said,... 'bout any current issue 3.0l or 4.3l motor, 'n drive will do everything you wanta do, 'n do it nicely....

Thanks bondo!

I'll broaden my search!

Is the switch to Volvo/Mercruiser because of parts availability?

jeremycanfield said:

Is the switch to Volvo/Mercruiser because of parts availability?

Click to expand...

Partially!
Let me be brutally honest with you!
This is an OMC Stringer Drive. It was a poor design back in 1969, and is still a poor design today.
Even if you were to get all working, you'd be asking quite a bit of this to carry 8 people, let alone pull any tubes.

In order to change to Merc or Volvo Penta, the transom cut-out area would require an in-fill. This is due to the size of the StringerDrive opening.
I believe that there is an adapter plate (if you can still find one today) that closes the opening down for an AQ series Volvo Penta. There may also be one for the Merc.

If up for the task, you'd be ahead of the game if you were to replace this with a Volvo Penta. Merc would be my second choice.

Or... cut your losses now!

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I love brutal honesty, although that was a very soft form of brutal. Thanks Ricardo!

Honesty is exactly what I need!

The transom repair does not appeal to me but if its necessary to have the right set up, I'm comfortable with it. I'm a professional handyman and a terrific problem solver, so I'm confident I can manage with the right support (knowledge and info).

I have tracked down a couple of Volvo options. One is a local AQ120/Penta 270 that I can probably pick up for a couple hundred bucks, but it has none of the controls and needs going through-it has been sitting outdoors (I don't know how long). That leaves me with a better set up but no additional power and I can imagine it will get pricey finding the controls, etc. (unless I can use some of what I have-I'm guessing not)

The other is a Ford 351/Penta 270. The 351 was "rebuilt" and put in place of the original 302. The seller said he has not done anything with the outdrive but I thought you were supposed to re-gear the lower unit for different motors. That boat has been sitting for 6 years. I think that is too much power for my set up-What do you think? There are a lot of unknowns, but maybe worth a drive (300 miles each way). They want $1000!

There is also a 228 Mercruiser in a Wellcraft. Its 2 blocks from me and has been on the side of the road for a month. I think I can get it for $5-600. That seams like a great option if the 228 is a good unit.

I could also modify the transom or build a bracket for an outboard. Any thoughts?

Thanks!

Go with the 228.The older Volvos if running are a great motor. But can be VERY costly. The original boat is aluminum. Alum scrap can go as much as $.99 a pound?? Like Rick says the old OMC is a money pit. No one wants to work on them. E-bay the drive. The 228 is a Mercruiser,the parts are everywhere and everyone works on them. Parts are cheap compared to Volvo. Do a compression test.Check the plugs for rust.The drive oil for water? Good luck.

Jeremy, first of all...... in order to make sense of this (i.e., an engine/drive conversion), you'd need to really love this hull. Not only love the boat, but be convinced that it suits your needs across the board.
You'll be in for a transom core replacement, and an outer aluminum skin re-work of some type.

Don't get me wrong..... I too love these projects. I've done 5 fairly complete personal boat restorations, and I've done plenty of this stuff for customers.

IMO, the Volvo Penta will be the better of the two drives. Plenty of good used parts out there.
The AQ120 will still under-power this boat.
The 5.8L Ford would be OK, but possibly offers more power than what you need.
V/P parts for the Ford engine are available in the used market.


An AQ145 is V/P's OHC 4 cylinder engine, and would be a good choice.
The engines hold their value, but the drive components are a dime/dozen because of supply/demand (I.E., you can't wear these out).



Volvo Penta = Cone Clutch gear engagement.... no SI system.
Volvo Penta = OHC 4 cylinder engine (after the push rod engines).

Merc in the smaller engines = Dog Clutch gear engagement and the SI (shift interrupt unit).
Merc in the small engine = GM push rod engine.

If you go Merc, go with a later year model..... at least something in the 90's.

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Thanks Jerry and Rick!

The Mercruiser owner is firm at $800. I don't think I was super clear on that one, it would be a donor boat only--the interior is gone and what's left is a mess. It turns out it has been sitting for 6 years as well. Does that happen in your neck of the woods also--do people just neglect them and leave them sitting?

I can't bring myself to make the 600 mile round trip to check out the Ford/Volvo unit. I think I am going to find junk when I get there.

At this point I am just watching and waiting for the right set up. There is a Volvo straight 6 in a Bayliner that I need to go see. If I go the Volvo rout, does it make sense to pick up the 4 cyl/Penta 270 unit for parts/second drive ($200-300)? One other question on the Volvo. What is invloved with using a non-Volvo engine with the Volvo outdrive-I'm guessing its pricey?


In the mean time, I've looked over that GM 153ci and it looks relatively clean. The previous owner also had two carburetor rebuild kits stashed in the boat. I'm going to get it running and go fishing!

Thanks so much for your input!

jeremycanfield said:

Volvo straight 6

Click to expand...

you don't want that

You want a Mercruiser Alpha One with a Chevrolet based V6 or V8
another choice would be VP AQ series behind a Chevrolet V6 or V8

anything else would be a pass. wait for the right thing

not sure whatever happened to your project but I have a 1974 Crestliner Norseman that I repowered with a Mercruiserstern drive and use my original 3 liter Chevrolet engine. I found a donor boat that had a Mercruiser setup that I was able to remove to get the mount plate the gimbal housing and the drive itself. the 3 liter GM has been more than enough power with 5 people on board and a couple of kids on the tube I believe it's rated at 140 horses,filling in the transom plate is very easy to do.

This thread is well over one year old..... but I too am curious as to his decision.

Im hoping that he found a good AQ series drive and engine.


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