Overhaul advice needed

[pip_11]

Hi All,

This is my first post to the forum and like many newbies We (Wife and I) have just purchased a new to us sailboat. Specifically a 1976 30' C&C MKI which has an Atomic 4 engine in it. Engine hours unknown - there are two removed engine hour counters, both over 4000 hours. Not sure which belongs to the boat (maybe both?!).

Please note that neither of us are that mechanically inclined but have some experience with mechanical things ie. lawnmowers etc..

The Engine is currently running however we have some concerns for its condition and reliability on a going forward basis. Issues we have are:
1. We are getting significant amounts of fumes whilst it is in operation
2. We are getting significant amounts on fumes when it is sitting at the dock for a couple of days
3. The previous owner did some jerry rigging of the thermostat to the point where he put a manual valve in to control the temperature, then ran it at approx. 140 degrees F.
4. We have some significant corrosion on the of the engine pictures attached.
5. There is a fair amount of chugging on startup. Takes a while.

We have just done a cold compression test and the results were on cylinders 1&2 were at 115 psi. Cylinder 3 initially was 80, I tightened the compression screw and tried again and got 95 ish, I then tested the 4th cylinder and we got 105 psi. I then put a little bit of motor oil into the cylinder from the sparkplug hole and retested the 3rd cylinder and got 95ish again. So am thinking we have a sticking valve, no?

As a result we are thinking we will pull it apart over the winter - have the engine cleaned and honed and then rebuild. We have already purchased the overhaul manual and parts list from Moyer, however any advice of the things we should do would be appreciated.

We will likely be putting a electronic ignition and fuel pump in anything else we should be planning on doing/adding to the actual engine itself? Possibly alternator?

Attaching pictures for reference!

Thanks for your thoughts.

Regards,
Philip

[Al Schober]

I'll take your questions in order.
1. Fumes in operation. If exhaust, you'll have to replace the hot piping. The photo shows this may have been done recently, at least leaving the manifold flange. If the fumes are coming from the oil fill or breather, replacing the rings should correct this.
2. Fumes when sitting. Suspect you're smelling gas and that your hoses are original. First suspect IMHO is the fuel fill between the deck and the tank. Give it a squeeze - might just crumble in your hand. All older fuel hoses were not meant for ethanol fuels and are suspect.
3. T'stat hoses. Lots of ways, kinda like skinning a cat. I've seen engines with NO bypass plumbing (and no thermostat). Yours looks unusual but not unreasonable.
4. Corrosion. What I see looks pretty good. Bad areas are usually under the water jacket cover plate (corrected by changing to studs) and under the original water pump (rebuild/change the pump).
5. Chugging. Need more info.
Don't think you have a stuck valve. Compression would be more like ZERO. Have the shop do the valves and valve seats. Carbide inserts for the exhaust seats are reasonable.
No experience with EI. Electric fuel pump is good (gets rid of the leaky settling bowl) but don't forget the oil pressure safety switch.
Alternator upgrade is good. With the original 35A, the charging voltage is too low. An external regulator (Balmar?) will raise the voltage, but I'd also recommend going up to about a 60 A alternator. The existing single belt will handle it easily.
Check the aft seal on the transmission. Easy to replace while the engine is out. Actually, if the engine is out, replace it anyway!

[Peter]

Hi Phillip and your wife,

Welcome and congratulations on the new boat!

Fumes are a concern. What kind of fumes?

When running - Exhaust fumes? - smoke from the oil fill? Gas fumes?
When you return to the boat? Gas fumes?

If you have gas fumes they must be dealt with immediately as they pose a significant explosion hazard.

3) The bypass valve with no thermostat is a standard mod that many on this form have made. If you were to purchase a brand new engine from our host it would have such a valve installed - but would run a thermostat.

4) Corrosion - does not look that bad to me. And it looks like your hot section on your exhaust has been replaced recently.

5) I would think a sticking valve would give you much worse compression numbers than what you are seeing.

If you are getting fumes from the oil filler when running it could be a lot blow-by from rings on #3 and #4 that are a bit worn.


Electronic ignition - some here like it, others do not. If you do go that route, be aware there are potential issues around your coil overheating due to the increased dwell angle. The fix is easy however.

Electric fuel pump - ditto - some here like it, others do not.

Chugging on start up - have you verified that the choke is fully opening and closing? The A4 likes/needs choke when starting.

If it were my engine, I would not be seriously contemplating a rebuild with these symptoms.

I wonder if others can make some suggestions with respect to the compression and possible remedies?

Best regards,

Peter

PS - Al types faster than me

[pip_11]

Hi,

Thanks for replying quickly!!

Will try and answer all of your questions comments.

The fumes in operation are not fuel but aren't straight exhaust, not really sure how to describe it!

Whilst sitting think it's gas and something else again not really sure, I have been trying to figure it out, will take a look at the hose between the tank and filler as I haven't looked at that yet!

Feel better bout the thermostat after your comments however will end up putting a new one in, guess I'll just leave the manual one installed for emergencies though!

have made sure the choke is all the way out but haven't verified that it is doing anything, I would say that the engine takes 30 seconds to start to fire and then another 30 seconds to fire and run.

I realize the corrosion could be worse however just want to make sure we are ahead of the curve and can save ourselves headaches later on.

Thanks,
Philip

[msmith10]

Hi, Phillip. I've got a 1977 C&C30 Mk 1 and I've redone almost every system on the boat. Mo on this site has one of similar vintage.
There are lots of people on this site who can give you better advice on the engine than me, but if you need other info or advice on the boat itself in the future let me know. It's a great boat- easy to sail, very stiff, and still very competitive in PHRF racing.
From what I see in the photos you've got a pretty good looking engine. By the way, it's a Stevedore model of the A4, as is mine. The only difference with the non-stevedore model is the insertion of a restrictor ring in the carb throat which was meant to circumvent some HP restriction of imports from Canada or some such thing. It was pressed in and is easy to remove by simply prying it out if that hasn't been done already.

[msmith10]

Hi, Phillip. I've got a 1977 C&C30 Mk 1 and I've redone almost every system on the boat. Mo on this site has one of similar vintage.
There are lots of people on this site who can give you better advice on the engine than me, but if you need other info or advice on the boat itself in the future let me know. It's a great boat- easy to sail, very stiff, and still very competitive in PHRF racing.
From what I see in the photos you've got a pretty good looking engine. By the way, it's a Stevedore model of the A4, as is mine. The only difference with the non-stevedore model is the insertion of a restrictor ring in the carb throat which was meant to circumvent some HP restriction of imports from Canada or some such thing. It was pressed in and is easy to remove by simply prying it out if that hasn't been done already.

The fumes may be blow-by. These are meant to be sucked into the carb via a short rubbber tube which goes from the side plate to the area of the flame arrestor. If there is a lot of blowby, the carb vacuum just isn't enough to suck out all the fumes. Make sure you are running the blower anytime the engine is running (which you should do for safety reasons anyway) and leave it running for a few minutes after shutting the engine off to get fumes out of the engine compartment.

[pip_11]

Hi Mark,

Will likely take you up on systems issues as we have a significant amount of work to do on her!

On the blower issue we haven't been running it when motoring, maybe I should have been so that may be my issue, but the amount of fumes coming off of the engine is significant.

Thanks,
Philip

[Marian Claire]

Welcome to the forum.
I hope there is a bit of space between the exhaust and that hose below. The pipe should be wrapped from the manifold exit to the wet/dry junction. It gets very hot.
If the cooling system is functioning now I would not change anything until you know what you have and understand the flow. When I bought the MC she had a big wad of hoses and fittings in the cooling system. But it worked. After working thru the mess and having a better understanding of what the PO had done I started making changes.
My system has a manual valve and no T-stat.

Dan
S/V Marian Claire

[msmith10]

The safety reason for running the blower is to exhaust gas vapors so you don't have an explosion if there are fumes built up in the bilge. You should start the blower before starting the engine. Sniff the blower exhaust for gas fumes and don't start the engine if you smell any. On our boats it's easy just to open a lazarette and smell for fumes also.
Running the blower anytime the engine is running also helps exhaust blow-by fumes.

[msmith10]

Like Dan said, get some exhaust system wrap and cover up that hot exhaust (the exhaust line from the manifold to the point where water is injected). That's both a fire hazard and a guaranteed 2nd degree arm burn at some time in the future.
It may be a distortion in the photo but your freshwater cooling pump belt looks rough just to the left of the crankshaft pulley.

[Mo]

Hot exhaust appears to be fairly recent and the fumes might be because it hasn't gassed off. Every piece of metal has an oily residue on it to keep it from rusting / corrosion from the time it's made until delivery. Sometimes it can make fumes for hours and hours after installation.

Is the smell inside the boat or outside the boat....outside could be a carb mixture issue. Inside is exhaust leak, burning off oil on new parts, or blow-by which is also common.

Your compression numbers are not outrageous...3 are near perfect. The engine doesn't look too bad.

Looks like you might have fresh water cooling installed on that....most of the people I know who have both raw water and fresh water cooled (the antifreeze reservoir) don't use a thermostat and keep a by valve. I've done it for years and continue to do so....never had an overheating issue.

You have an engine that starts. You have decent compression....take a video of it running and send some pictures of the whole exhaust from the back of the engine forward. If someone worked on that exhaust we need to ensure it's done right.

PS: If you smell gas upon going in the door, I mean the smell of gas like you are filling your lawn mower...that is a leak so you need to find it. There is no gas smell when I go to my boat. I wouldn't even turn on the power if I smelled frank gas upon entering a boat.

[pip_11]

All, thanks for all of your replies!

We will be wrapping the exhaust during the winter!

Yes we have fresh water cooling and it looks like it was done a significant while ago as the heat exchanger looks to have been there for a while.

I'll take a video of the engine running likely on Thursday which will be the next time I'm down at the boat.

As for the fumes when we get back to the boat, I'm not really sure what it is. There is definitely a gas smell but also something else to it.

Thanks Philip

[Hawkeye54]

Phillip, I was not able to readily identify what type of pipe was used for exhaust replacement - please be aware that if galvanized pipe was used, the pipe can generate some nasty fumes as it heats up.




Rick