What should I do with my 3.0?

[Plasma George]

Hey Guys,
I want to sell my boat, but need advice on what to do with the engine that's running rough.

I have a 1988 Chaparral 3.0 I/O with a Mercruiser Alpha One, with compression 60,100,100,100. It takes a lot of cranking to start, even when warm....the previous owner commented it needs to be tuned up.

I'm not sure whether the compression has been like that for a long time, or just happened when I over-heated and burned the impeller last Fall.

I want to sell it, but everyone is quoting me $1000 for a head gasket that "may" fix the compression, and that's too much for a $3000 boat.

Should I sell as is ?
Not disclose the compression issue ?
Will new plugs/cap smooth out the idling and have it start with less cranking ?

Part of me doesn't want to pass any issues and lie to a new buyer, but if the 1988 has had compression issues for years, and this engine will run fine for years (and I bought it like that) I have no problem. It gets to 40+ mph, and runs as strong as the day I bought it before the overheating day.
Thanks for your advice.

 

[Fishermark]

Re: What should I do with my 3.0?

Well obviously I would not encourage you to lie or hide any information... but the best thing to do is to tune it up and see if that helps. Do you have the ability to do that yourself? Who did the compression test and how did they do it? A boat that isn't running well will sell for FAR LESS that one that does.

 

[JustJason]

Re: What should I do with my 3.0?

with compression numbers like that, you'll never get it to idle correctly.

A leakdown test is in order to see why #1 is 40 pounds shy of the others.

The loss of compression is either in the head gasket, through the rings, or the valves aren't opening up all the way and sealing. Or a combination. Start with a leakdown on #1, and adjust your valves. If you do have a bad head gasket fixing it isn't going to get the other 3 cylinders over 100, and they really should be.

 

[Plasma George]

Re: What should I do with my 3.0?

Thanks, Yeah I can handle 4 spark plugs and wires, and I suppose that makes sense to see if that smooths it out a bit.

The compression was noticed by the Dealer who replaced the impellor and verified by an Individual, both confirming 60 on the one.

I overheated the engine on the water last fall, replaced the impeller and some rubber hoses on the exhaust and launched it 6 or 7 times before winterizing. Not 100% sure if that caused the compression.

I hear these engines are pretty durable, so if I were to keep it, I'd roll with it as is, and keep an I on the oil.

 

[bruceb58]

Re: What should I do with my 3.0?

Do the leakdown test and determine if it is more than just the head/head gasket. If its is rings as well, then obviously you are going to be talking more than just the head as you will be talking rings at that point.

I would definitley disclose this before you sell the boat. It will be up to you to determine if you will recoup the money it takes to rebuild the head. If it really would cost you $1000 to fix the items and the price of the boat would drop the corresponding $1000, it may be worth selling it "as is" assuming you can find a buyer. It is a tough market sellng a boat right now so if you don't fix it, you are limiting the number of people willing to take a chance on it.

 

[Plasma George]

Re: What should I do with my 3.0?

Do the leakdown test and determine if it is more than just the head/head gasket. If its is rings as well, then obviously you are going to be talking more than just the head as you will be talking rings at that point.

I would definitley disclose this before you sell the boat. It will be up to you to determine if you will recoup the money it takes to rebuild the head. If it really would cost you $1000 to fix the items and the price of the boat would drop the corresponding $1000, it may be worth selling it "as is" assuming you can find a buyer. It is a tough market sellng a boat right now so if you don't fix it, you are limiting the number of people willing to take a chance on it.

Thanks for all the advice.

What if a tune up has it running smooth ?? Can an older engine have compression numbers like this and stll proved years of boating?

I never did a compression test before I bought it last year, so I can't be 100% sure if it's been like this for years. The previous owner only had it for a year, from the original owner.

 

[mciaio]

Re: What should I do with my 3.0?

Overheating it scored the cylinder walls on the one cylinder, a head gasket or tune up will not fix the issue.

Sell it as it, but tell the new buyer.

 

[JustJason]

Re: What should I do with my 3.0?

What if a tune up has it running smooth ?? Can an older engine have compression numbers like this and stll proved years of boating?

No the compression is to low. It has to be 100psi minimum on all cylinders. And that 100psi is a bare minimum. It really should be 140-150psi on that motor. If the compression is to low the motors will not reliably run + they won't hold a proper low in gear idle + they won't make full rpms.

 

[bruceb58]

Re: What should I do with my 3.0?

Overheating it scored the cylinder walls on the one cylinder, a head gasket or tune up will not fix the issue.

You don't know if any scoring occured. Could easily be a warped head. The cylinder leak down test will tell you that info.

 

[mciaio]

Re: What should I do with my 3.0?

You don't know if any scoring occured. Could easily be a warped head. The cylinder leak down test will tell you that info.

Your right, but regardless, a head gsaket or tune up will not fix either issue. My opinion is that it is something mechanical.

 

[Plasma George]

Re: What should I do with my 3.0?

I sell Onan generators, and I'm very good friends with one of our Dealers, he's very talented with engines...I sent him this thread link. Being a Cummins employee, I get Mercruiser parts at distributor net, so that part is good, but we're still talking some good labor no matter what.

Sounds like I shouldn't even bother with a tune-up attempt. You guys seem right on, I just don't know if the compression has been like this for quite some time or not.

I only saw the boat run 1 time and don't recall the rough idling, but I do recall the hard starting. I remember the guy being embarassed moving the thottle up and down to get it to turn over...and it's still like that. This is a much bigger issue than the rough idling. This can't be hidden in front of a potential buyer.

When I say rough I mean it's a bit unsteady 700, but it's pretty smooth at 900. I can stare at it with the belt spinnning and a pencil will sit on the head. (maybe shake off at 700).... I just read here that it's not a good idea to keep engage the drive at 900 rpm.

 

[JustJason]

Re: What should I do with my 3.0?

When I say rough I mean it's a bit unsteady 700, but it's pretty smooth at 900

Correct, which Is why I said earlier....

If the compression is to low the motors will not reliably run + they won't hold a proper low in gear idle + they won't make full rpms.

If the leakdown test shows a bad head gasked on cylinder 1, but shows worn rings on 2,3 and 4, it's time to start looking at a new or used block, or a rebuild of yours. Even if a new headgasket got all 4 cylinders to 100psi, that's still on the weak side.

 

[Plasma George]

Re: What should I do with my 3.0?

I'm not too concerned about being on the "weak side", I guess I should've said 110, 110, 110, 65. That's what the Dealer officially documented.

We can haul at 40-45 mph with the engine in the condition it is now, so I'm OK with it's power. All I want is a smoother idle and easier starting, and not having a worsening situation for another owner down the road.

I'll keep you guys posted, cause I may need help is a major decision has to be made.

 

[bruceb58]

Re: What should I do with my 3.0?

When I say rough I mean it's a bit unsteady 700, but it's pretty smooth at 900. I can stare at it with the belt spinnning and a pencil will sit on the head. (maybe shake off at 700).... I just read here that it's not a good idea to keep engage the drive at 900 rpm.

Start shifting your drive at 900 RPMS and you will have a bad drive to go along with your bad engine.

 

[system-f]

Re: What should I do with my 3.0?

This is how I bought my boat. Overheated and running on 4 of the 6 cyliners, actually it was 3 at first. The cost to fix this was less than $300, BUT I HAD NO LOWER ENGINE ISSUES!

First I had to have the head resurfaced as it was warped very badly. My head is much longer than yours being a straight 6 and yours might not be warped as a badly. This only cost $95

Then I pulled the valves and reground the seats. Really I need to have the seat work done by a machine shop as they were worse than I expected, but I did get them all to seal once done. This cost me $3 for valve grinding compound.

Finally I put the engine back together and all of my compression was within min. limits. Now I haven't checked compression lately, but I bet it is a lot higher as this engine sat for sometime and I have no doubt the rings were somewhat stuck. It kept running better and better as the season went by.


I WOULD NOT continue to run the engine how it is even if it goes eleventy billion miles an hour. Working on this engine is a step above a lawn mower and NOT difficult at all.

 

[Plasma George]

Re: What should I do with my 3.0?

So my mechanic friend went over the engine and made some minor improvements to where it's running much smoother, not stalling and starting faster.

4 new spark plugs, corrected the "out of whack timing", something to the choke that improved the starting. It's idling at 600RPM. He said the compression was higher than I said, but still low.

I don't think we're going to pull the heads, and do any major engine/cylinder work. He commented he feels "blow by" from holding his hand over the carb with the air cleaner off ???? I think.

As a final "minor tweak"... he wants to do a valve adjustment, but he's not 100% sure how to do that on this engine. Can anyone guide on this procedure so I can forward it to him ?

 

[floater180]

Re: What should I do with my 3.0?

Maybe you ought to try using Sea Foam or some other kind of intake cleaner. This will clean up the valves and create a tighter seal.

 

[bomar76]

Re: What should I do with my 3.0?

I don't think we're going to pull the heads, and do any major engine/cylinder work. He commented he feels "blow by" from holding his hand over the carb with the air cleaner off ???? I think.

As a final "minor tweak"... he wants to do a valve adjustment, but he's not 100% sure how to do that on this engine. Can anyone guide on this procedure so I can forward it to him ?

1. There is no blow by coming out of your carb.

2. It has hydraulic lifters and preload is adjusted like any SBC or BBC engine.

3. The proceedure for adjusting preload is in the manual, they are FREE downloads at the top of this forum (Adults Only thread)

4. He may be your friend, but he is certainly not a mechanic.

 

[Bondo]

Re: What should I do with my 3.0?

As a final "minor tweak"... he wants to do a valve adjustment, but he's not 100% sure how to do that on this engine. Can anyone guide on this procedure so I can forward it to him ?

Ayuh,... It's the Same as any Chevy motor built since the 1960s...

 

[ENSIGN]

Re: What should I do with my 3.0?

You got a bad cylinder/Head gasket. If you were buying it you would not want to get screwd!