Smoke in engine compartment

[Dpmmvc]

I am looking at a 1989 Catalina 30 to buy. It has a universal m25. It’s been on the hard for 2years. I started it on land for the first time in awhile and jogged down to the engine to take a look. This was a dry start and no water was used. I planned to shut the motor off before it got hot. I immediately saw smoke in the engine compartment . The motor had only been on for 20 seconds at this point. I was alarmed and shut the motor off within 2minutes of starting it. Engine never got hot and I’m at a loss to what would cause this smoke. It wasn’t a lot of smoke just a little foggy and it smelled similar to exhaust. Thoughts?

[Wotname]

Welcome aboard CF, Dpmmvc.

There could be many things wrong that will cause smoke considering the boat has been on the hard for two years - presumably no maintenance has been done in that period and quite possibly, the boat had faults predating this period.

I would start with the easiest - broken exhaust system and the exhaust was venting inboard.

Presumably it is a wet exhaust so it will need water for cooling although it should have been OK for 20 seconds.

Also running the engine with no water available for the raw water pump will destroy the impeller in short time considering it was likely to be dry after sitting for two years.

[StuM]

I second the leaking exhaust as the first place to look. But it could also be just a stuck/slipping fan belt. I've seen then generate a lot of smoke at startup. Any black residue around the engine afterwards?

[Dpmmvc]

I didn’t look for any black residue. Would an exhaust leak appear that soon after startup? What can I do to check it once and for all?

[Wotname]

Originally Posted by Dpmmvc

I didn’t look for any black residue. Would an exhaust leak appear that soon after startup? What can I do to check it once and for all?

A small leak might not but it is possible the exhaust system is completely broken and discharging some/most/all the exhaust inside the hull. I don't the know the details of this particular boat but usually there are several components of the exhaust system from the manifold to the water injection point (mixing elbow), a water trap, possibly a gooseneck, possibly a silencer, lots of flexible exhaust hose, lots of clamps, lots of things to fail. By the way, presumably a wet exhaust so it should not be run dry except for a few seconds (say 10 to 30 IMO).

Was not the owner or broker or someone else on board who would know more detail?

Me, I would eyeball everything around the engine, arrange for a wet start (water available to the raw water pump via a container - not a hose into the though hull fitting), have someone start the engine while observing everything from below and look for where the smoke is coming from. There may even be a starting switch somewhere in the engine compartment!

[Dpmmvc]

If the exhaust system is completely broken.., how expensive of a fix are we talking?? I’m assuming that this is the worst case scenario and if so I’d be willing to have it fixed if it’s not an expensive fix. The boat is in immaculate condition and I would be getting it for a steal.

[wsmurdoch]

We once had a loose injector that put smoke and soot into the engine compartment. Loosening the two nuts that held the injector in place then retightening them alternately and evenly fixed the problem.

Bill

[CassidyNZ]

On my boat (may be completely unique but . . . .) has a glass fibre elbow connecting the engine manifold to the rubber pipe leading to the waterlift. If my engine runs for even a very short time with no raw water in the exhaust, the elbow effectively burns away. Happened with a raw water impeller failing, filled the engine room with unmistakable exhaust gas in a couple of minutes.

I was lucky enough to rescue the elbow before it was completely destroyed and rebuild it.

[Dpmmvc]

Here are a couple of pictures of the motor. I tried to upload a video of it smoking but it wouldn’t let me.

[Dpmmvc]

In the video I have it almost appears there is a fine strip of smoke coming from the fresh water heat exchanger.. is that possible?

[boatpoker]

Can never be sure from a photo but I suspect .....

1. New exhaust lagging ...... what is it hiding.

2. Corrosion seeping from under new exhaust lagging.

3. End caps of heat exchanger leaking.

[skipperpete]

Originally Posted by Dpmmvc

In the video I have it almost appears there is a fine strip of smoke coming from the fresh water heat exchanger.. is that possible?

Yes it's possible to have exhaust smoke from the coolant filler if there is sufficient corrosion in the heat exchanger to allow the coolant side to connect with the raw water side. The exhaust gas enters the raw water system at the mixer elbow or injection point and blows back through the raw water pipes. There are other threads on the forum that show a direct connection between the exhaust system and coolant side at the exit flange in your photo. Also a leaking head gasket can cause exhaust from the coolant filler.
The intake air cleaner appears to be in need of attention too.

[GILow]

Probably not relevant in this case but worn engines can smoke quite dramatically through the crankcase breather. If it is not connected to the intake manifold you’ll get a lot of smoke very quickly.

[Island Time O25]

Just curious, what is a "steal" price on a 30 yr old C30?

[Dpmmvc]

After reading all of this I dont think it’s such a steal anymore, but $11,000 was what we agreed on. It needs new chainplates and halyards. The bottom is in need of soda blast and bottom paint. Other then these things the boat looks new . 1989 Catalina 30 mkii wing keel. My knowledge (as you can tell) is very little on motors. I really appreciate all these replies. I think I will pass on this boat.