1987 Merc 4.3 Rebuild or replace?

[achris]

Just checked the spec on your 185. Who told you the recommended was 4200-4600? (hint: it's not!)


If all you were pulling at 'normal' load was 4400, and you added a few more ballast units, and tried to ski.... Little wonder that engine carked it!

 

[timharper89]

Just checked the spec on your 185. Who told you the recommended was 4200-4600? (hint: it's not!)
View attachment 350544

If all you were pulling at 'normal' load was 4400, and you added a few more ballast units, and tried to ski.... Little wonder that engine carked it!

I misspoke (typed?) with my first WOT rpm. I'm running 4600 at WOT. I looked it up myself in my manual (#7 I believe) as well.

Yes and no. 4400-4800 is the spec, but as most of us rarely run at WOT all day, 5000 isn't going to hurt anything. And since you want to ski, you are most definitely OVER-propped at 4400 (despite it being 'right in the middle')... The recommendation for skiing is to find the size of the 'right' prop (at or near the top end of the range), then drop down another 2"..

Seems like I should just have 2 props maybe? We don't ski very often. Then again, maybe just lowering the pitch will make us happier all the time. Definitely something I will look into

That may be down to a dying engine. Or it could be just the hull design. It is only 185hp.

Maybe a bit of both? It does have a 20 degree dead rise, which I've read makes it a little slower and harder to plane than a boat with a smaller dead rise but better ride through rough water.

If you are having trouble staying on the plane, move the ballast (passengers) forward. I know they love congregating at the back of the boat, which forces the stern down. Tell them to move forward, or get off the boat!

A little more difficult with a cuddy cabin that doesn't have comfortable seating up front. Just a low ceiling. Hope you don't bump your head! One reason we want to upgrade.

You might lose a knot or 2 but since, as I said earlier, we don't stay at WOT all day, it's a very small price to pay.

Again, this definitely is something I'll look into. I always assumed that since I had trim tabs and a 4 blade prop and was in spec that I was just kind of stuck with an underpowered motor.

Chris.....

 

[achris]

I always assumed that since I had trim tabs and a 4 blade prop and was in spec that I was just kind of stuck with an underpowered motor.

You could put a 330hp big block in that boat, over-prop it and feel the same way, under-powered. Similarly, we could put a 140hp 3L in and prop it correctly (right at, or a little over, the top of the recommended rev range) and you'd have great fun...... As I said earlier, propellers maketh the boat.

Chris...

 

[Lou C]

A few things…as far as propping I would always rather be on the upper end or even as high as 5,000 because that allows for heavier loads or rough water conditions that force you to run bow up to keep the boat from getting swamped; or for water sports. In the long run as long as you don’t exceed 5,000 regularly you will be better off because in all the high load conditions the engine will be less stressed. Over propping causes a spike in combustion chamber temps that damages exhaust valves (burning, tuliping) and low compression.
Next, instead of focusing on costs per se I would look at it this way, you are spending money either way and keep in mind self repair is not risk free. You are the mechanic parts finder and warrantor. It breaks again you get to fix it again. My thought would be find a machine shop local to you that can do it and guarantee it. Then you have a boat you can use without worry and can sell with clear conscious. Keep in mind any used boat you buy will be overpriced now at least in most places. Do as Rick said, check the structure as best you can. Then get the 4.3 rebuilt and enjoy it.
Junk yard, mail order all have added risk and inconvenience, and take up your time.

 

[achris]

…as far as propping I would always rather be on the upper end or even as high as 5,000 because that allows for heavier loads or rough water conditions ...

A man after my own heart!

 

[timharper89]

A few things…as far as propping I would always rather be on the upper end or even as high as 5,000 because that allows for heavier loads or rough water conditions that force you to run bow up to keep the boat from getting swamped; or for water sports. In the long run as long as you don’t exceed 5,000 regularly you will be better off because in all the high load conditions the engine will be less stressed. Under propping causes a spike in combustion chamber temps that damages exhaust valves (burning, tuliping) and low compression.

That makes sense. I'll be taking that into account for sure in the future.

Next, instead of focusing on costs per se I would look at it this way, you are spending money either way and keep in mind self repair is not risk free. You are the mechanic parts finder and warrantor. It breaks again you get to fix it again. My thought would be find a machine shop local to you that can do it and guarantee it. Then you have a boat you can use without worry and can sell with clear conscious. Keep in mind any used boat you buy will be overpriced now at least in most places. Do as Rick said, check the structure as best you can. Then get the 4.3 rebuilt and enjoy it.
Junk yard, mail order all have added risk and inconvenience, and take up your time.

My boat isn't worth the $4000+ I would have to pay to get it rebuilt. I'm just looking for a few michigan seasons of use, and we don't have a huge budget to begin with. I think we would just go without a boat rather than pay 4 grand. I can buy a mid to late 80s boat with a newly rebuilt engine for around 4 to 5 grand. Almost bought a mid 90s in stellar condition for 6 grand but thought about it too long and missed out. If I can spend 1-2k and get a working boat for a couple years, it comes with some risk, of course, but if it works, I can sell it after the market goes back down and break even. I already have other things I need to take care of before selling with a clear conscience. Completely redoing the trailer brakes and a new coupler are a couple of those things. I'll discuss these options with my wife, but she's more of the mind to just get rid of it and don't worry about it or sink any more money into it. She doesn't have the patience and vision I have .

I can buy a rebuilt long block for 2k. I guess I could call around and ask how much to rebuild if I bring them the motor. Not sure on the cost of that.

 

[Lou C]

Keep in mind any late to mid 80s boat, yes even in freshwater can have a lot of rot in the structure depending on how it was stored. I would not advise anyone to buy a boat that old. If you think engine repairs are epensive, well wood/composite fiberglass repairs are a lot worse, more time consuming, and even more expensive. IF you have a boat with solid structure and a bad engine, a reman engine is the least risky way to get a reliable boat. Someone else's mid to late 90s boat, rebuilt engine, a lot more risk. There is no free lunch. And yes I had to go through a partial deck/stringer repair and I can tell you it was a good deal more than 2 grand.
Next boat I buy will buy will be no more than 5 years old and outbord powered only.

 

[timharper89]

So I called a local shop. If I bring in my block disassembled, he'll get it back to me disassembled with all new internals for $1200-1500 ish. He says he has no markup on parts and sells them for the going online price. He sounded like a straight shooter who takes his work seriously. No written warranty, but he says he stands behind his work. Obviously guaranteeing things can be a little trickier when I put it together. My wife is still apprehensive about putting the money into it. She's much more of a cosmetic person, and there are definitely things that could be addressed like the seat vinyl and a missing window, etc. Not sure what route to take at the moment. If somehow a bunch of stuff becomes a problem next year, I'll never hear the end of it

 

[nola mike]

So I called a local shop. If I bring in my block disassembled, he'll get it back to me disassembled with all new internals for $1200-1500 ish. He says he has no markup on parts and sells them for the going online price. He sounded like a straight shooter who takes his work seriously. No written warranty, but he says he stands behind his work. Obviously guaranteeing things can be a little trickier when I put it together. My wife is still apprehensive about putting the money into it. She's much more of a cosmetic person, and there are definitely things that could be addressed like the seat vinyl and a missing window, etc. Not sure what route to take at the moment. If somehow a bunch of stuff becomes a problem next year, I'll never hear the end of it

Not sure why you don't just get a wrecker block. $1k cheaper, saves you a *ton* of time. A truck engine going bad is rarely the reason it's in the yard...Usually they offer a 30 day warranty or something. Check compression. You won't have to worry about any internal rust or cracked block like a marine engine, and chances are it's had an easier life.

 

[timharper89]

Not sure why you don't just get a wrecker block. $1k cheaper, saves you a *ton* of time. A truck engine going bad is rarely the reason it's in the yard...Usually they offer a 30 day warranty or something. Check compression. You won't have to worry about any internal rust or cracked block like a marine engine, and chances are it's had an easier life.

This is my preferred option. Wife doesn't like to gamble. Also most of the trucks I have found don't appear to have any collision damage. Other than transmission or engine issues, why else would you junk a vehicle?

 

[Lou C]

I would not do a junkyard engine but that's just me. I want it taken apart, everything measured, and put together by a machinist. If you put this together yourself and do something wrong, imagine how mad your wife will be. I'm not saying that you can't find a good junkyard engine but I think if you want reliablity you will wind up going through it just like going through your own.
Keep in mind you are not getting a decent boat, for less than approx $15k in today's market. Those 25 year old "all redone" "water ready" boats you see for $4-6K can have all kinds of problems. I would not touch one, with a 10 foot pole. I've been through enough old boat repairs to know, what can happen. And keep in mind, an FW like yours new, is approx $46K.
Just one example, today I had the pleasure of removing my old (original) steering actuator because all the sudden it started leaking like crazy. So on a 33 year old boat what do you do? There are no new parts, you have to search for them. I found a good used unit and also was lucky enough to find new old stock for the actutator and power piston. Then get to fix it. First you pull the back seats, then the whole exhaust system, finally you get to deal with the 4 cotter pins from He!!, and lucky for me I always greased the steering cable so it came right off. If you could not do this yourself this is a $1500+ repair all by itself, depending on labor. When you can find them new these units are $900-$1000. That's why I say, no more of this for me. I learned enough not to have to do it AGAIN!
PS that cotter pin puller is worth its weight in gold no way could you do this job without it!