Planning on Buying a 1989 , 236 Mako Inboard??

[watermargi]

Hi All.

I am thinking of buying a 1989 Mako 236, true inboard, with a Mercruiser ,260 hp, salt-water cooled, engine. The Merc Engine only has about 220 hrs on it.

I have been told that I should be very careful about the condition of this engine, esp. about poss. over heating due to the salt water cooling system. Engine has been running very well ( according to the owner, my relative) as of about 1.5 years ago. Since Last time used. It has been stored indoors and maintained by the yard where stored.

The current owner says he has never changed the manifold risers/elbows. This is a concern of mine.

I just had the marina check out the Mercruiser V8 engine and they found salt water inside the engine/manifold. I had a compression test done, and it showed that one cylinder was leaking.

I got a quote from the marina to replace both sides of the manifold risers (Elbows?), and to put a new gasket on the one leaking cylinder.

The total estimate to do this work is about $3500.00

I am planning on paying about $5000 for the boat and trailer as is.

I am wondering if this is a fair price, considering the fact that the boat's inboard engine now needs about $3500 in maintenance?

Is this worth doing on this model 1989 Mako 236 inboard?

Do you think that the est. cost for this work is reasonable?

It is in pretty good shape I think, otherwise. Has some nice equipment too.

What do you think this boat would sell for in the current market?

Please let me know your thoughts?? Please See specs below.

Thanks very much for your help!

_____________________________________________

1989 24#8242; Mako

Inboard 350 ci Scorpion engine w/229 hrs

Hard T-Top with aluminum framing

Canvas Bimini

Standard Horizon GPS

Furuno Radar

Apelco Fishfinder/Sounder

VHF Radio

Battery On/Off Switch

Blower

Trim Tabs

Bilge Pump (manual/auto)

Cetol Woodwork/Trim

2- 60 gal Fuel Tanks (120 gal capacity)

Stored inside and professionally maintained yearly

[radioman]

You didn't say where you are located...

If you are saying they found water in a cylinder, and sitting over a year like that, you're going to be into more than just risers and manifolds...

You might be better off to find a "running take-out" to replace that engine.

https://miami.craigslist.org/pbc/bpo...804324314.html

You are unclear on the work that was quoted for $3500...

Both manifolds and both risers???

What gasket on "the one leaking cylinder"? - head gasket? - if a manifold gasket, they should replace both manifold gaskets if putting on new manifolds...

Just me thinking out loud, but 5K for 30 year old boat that may need a repower is kind of high.

[watermargi]

Sorry about that . I am in CT.

The repair the yard in Me. quoted is actually for both the elbows and the risers.

I think price is a bit negotiable now, since I asked these questions, and I found this stuff out about the engine.

The yard would plan to replace the gasket on the one cylinder that has a pressure leak.

Thx.

[rustyolddad]

watermargi

I built, and rebuilt, many inboard boat engines over the past 30 years. If that engine has water in the cylinder, especially salt water, I would be cautious. There is less than 100cc of free space in the combustion area of a cylinder. Squeeze some water into that area and iron starts to break: ie bent rods, bent valves and broken cylinder walls. In addition you will be amazed at how fast those cast iron parts rust when washed down from ingesting water! Think of it like this: pull some air and water into a cylinder, compress it and then catch it on fire. Can you say steam cleaner? Thats what water in cylinder does at super heated temps.

Who is paying the yard when they tear it down and find something else wrong? Where did that water go....probably oil pan. Ever see how water and oil mix? They dont and now we are talking bearing and crankshaft issues.

Plan on the worst....replacement engine and hope for the best.

[watermargi]

I Just rechecked with the yard in Me., and they said that the water was in the manifold/riser area of the exhaust system, it was not in the cylinder itself.

One manifold riser is fine, they said, but the other needs to be replaced, so they would do both the risers/elbows at once.

My primary concern is whether any of the cooling holes are plugged/blocked in the engine.

The boat ran fine according to the owner, last time it was run, and he be never had a problem with overheating.

The engine only has 220 hrs on it over 30 years.

I know .....it is still 30 years old.

Hoping for the best...... Thx

[cgmiller]

That is a high price in my opinion to work on a 30 year old engine. It may be due to the fact that none of the bolts are going to come out and they are all going to have to be drilled and retapped. You can buy a full manifold and elbow kit for $500 to $700 depending on the style. Hell for $3500, you can probably buy a complete crate engine..ebasic marine has a long block mercruiser for $1895...you might have to reuse some of the accessories such as the valve covers, alternator, water pumps, etc. https://bpi.ebasicpower.com/indmaren...0longblock.php

The last inboard boat I bought had a ebasic marine base engine. I added a fresh water cooling system, new edekbrock manifold and electronic ignition to it and it was awesome. I spent about $2000 to bring the engine up to par.

[cgmiller]

Another thing about low hour boats..to me, that means the boat has sat unused and slowly deteroriated..unlike a low mileage car that may have been started up and driven by an old lady every day to the store, a boat has sat neglected (in my opinion). I routinely buy old boats and fix them up over time..the worst ones were the ones that never got used and everything had to be replaced. You are going to need to replace the water pump, fuel hoses, water hoses, maybe some of the wiring, the exhaust hoses..anything that can sink the boat if it failed...the thru hull seacocks may not close...

[watermargi]

Re: I hear you.....Your comments--[i][b][b][i][i][i]"the worst ones were the ones that never got used and everything had to be replaced. You are going to need to replace the water pump, fuel hoses, water hoses, maybe some of the wiring, the exhaust hoses..anything that can sink the boat if it failed...the thru hull seacocks may not close..."

My Brother did use the boat annually for 2-2.5 months or so.

But clearly, if engine only has about 220 hrs on it, thencouldnt have used the boat a lot.

Boat Generally was put in the water sometime in Mid-June, then it was taken out in mid-September, and stored indoors. So really only in water for 3 months.

I am now thinking about replacing the orig. engine, if it can be bought for around $2200.00-$2500.00 , plus approx. $700 for the risers/manifold. The Question is should I try to change the cooling system, and make it fresh water, recirculating? Is this difficult to do?

I would Assume that labor for installing all of this would at least double the cost of the engine and new parts?

So at $3700-$4000 for the new engine, manifold-risers, poss. new cooling system ....total parts, so maybe about $3000-$4000 for the labor to install these??

Any ideas about this estimate?

I would have thought the labor/installation costs in Maine might be a bit less than in CT ?

Thx a lot for your help!

[mrdelgado]

quote:

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Originally posted by watermargi


I Just rechecked with the yard in Me., and they said that the water was in the manifold/riser area of the exhaust system, it was not in the cylinder itself.

One manifold riser is fine, they said, but the other needs to be replaced, so they would do both the risers/elbows at once.

My primary concern is whether any of the cooling holes are plugged/blocked in the engine.

The boat ran fine according to the owner, last time it was run, and he be never had a problem with overheating.

The engine only has 220 hrs on it over 30 years.

I know .....it is still 30 years old.

Hoping for the best...... Thx

---

I'd be more interested in hearing about this one cylinder that has low comp and where it's leaking.

Did the saltwater in the Mani make it to the exhaust valve and corrode a bit so it doesn't seat?

Aren't Manifolds routine maintenance on an inboard? They are only good for 3-5 years and easy to swap out. Trailer it home and do it yourself. crack a beer and watch a few youtube vids.

I'd also look into a freshwater cooling kit to extend the life of that block

[cgmiller]

Depends if the manifolds are fresh water cooled or sea water cooled,,fresh water aka antifreeze last a long time..the elbows are always raw water cooled as the exhaust and cooling water mix in the elbows...s for labor costs....yanking one out and putting a new one in is a one day task if you know what you are doing, I repowered my first 26 shamrock and me and a buddy had the old one out and new one in in one day.so I don't know what a marina would charge...maybe 16 hours start to finish.

[Noname Dave]

If the engine was raw water cooled you should not throw any more money at it.

If the boat is in good shape look for a replacement engine. As for being fresh water cooled, that is always good. How long do you expect to keep the boat?

[watermargi]

Thanks for the reply.

Just looked carefully at the Serial # of the MC Scorpion Engine.

This is not the original engine. ( This Mako 236 is a 1989)

It has apparently been re-powered.

It now has a Mercruiser Black Scorpion 350 ci, 315 hp. engine with velvet drive. Mercruiser Black Scorpion Serial # 0L002749.

Not sure of year was replaced, but I believe that this engine started in 1998??

Maybe that is the reason it has lower # of hours on it.