Catalina 30 Engine Smoke and No Throttle Control

[JBS Mystic]

Yesterday we sailed our 1984 Catalina 30 from her Larchmont mooring to the Mamaroneck marina for wintering. It's a short trip and we had fair winds most of way. When we entered the marina harbor channel, the wind died and so decided to flake the sail and motor in. That's when the trouble started. There was an excess of grey exhaust coming out the back and an engine alarm sounded. The motor continued to chug along, but the grey exhaust persisted. After ten minutes the throttle would not stay in position and the revs declined. Thankfully, we limped in to the marina, but throttle control was nearly gone.
Any thoughts on what might be the problem? She's forty years old and if Yanmar motor / transmission repairs are costly, I might just be done with the boat. We bought her two years ago from a friend as our introduction to sailing. On the plus side, she sails beautifully. On the debit side, we have no idea what might fail next.

 

[kappykaplan]

My first guess would be to check the mixing elbow. Was there a black sheen on the water? What specific engine alarm sounded?

 

[Don S/V ILLusion]

There are two ways questions like this typically go-

well-meaning people will offer guesses based on the (lack of) info you provide, or

better to provide more info which could narrow down the problem.

Age and history of maintenance of elbow as already stated. Other considerations -
integrity of throttle linkage, maintenance of injectors, cleanliness of fuel, condition of fuel filters, air filter clogged(if one exists), etc…

 

[Ralph Johnstone]

Same advice as @kappykaplan. Start with the simple (cheapest stuff first).

First of all, unfortunately your description of the problem creates more questions than answers so follow along here below.

1. Try to run your engine in neutral at the dock and describe what happens.

2. If the engine runs, leave it in neutral and try to increase the RPM. Describe what happens

3. Get a copy of a Yanmar manual .PDF from this site. It's there under downloads. You've just got to find it.

4) Following the instructions for removal of the mixing elbow and let us know what the interior looks like.

Understand that you've got a lot of work in front of you, but my guess is not a hell of a lot of cost. Yanmars are very forgiving.

Couple of other things to understand here :

a) you've got far more accumulated Yanmar knowledge here on this site than any low cost dock rat you may come across. We've got people here who take their engines apart just to see how they work and always insist that their engine run like clocks.

b) you must work in order - cheapest to more expensive . DO NOT install parts to see if they will solve the problem. You MUST deal with each part individually and provide a definite answer to each process you perform.

c) if you're not willing to do the work, tell us now. Don't waste our time.

The reason for this rather harsh statement is that in the last few weeks, we've had three nut cases drive the rest of us who were trying to help, almost to the point of going over the edge with their idiotic stunts. All three would do everything except what they were told and never reported what the results were .

Some members here like to work on engines vicariously by helping others with their engines but those three guys were enough to make some of us just want to ignore any further incoming questions on engines.

 

[dlochner]

Start with the simplest cheapest solution.

Inspect the cables and linkage. An example, recently in a crowded marina fairway with lots of expensive boats I lost reverse gear while trying to maneuver into a slip and then I couldn't get it out of forward and came into the slip at about 1.5Kts. Total cost of repair, $3.50 of which $2 was bus fare back from the hardware store. The nuts on the cable clamp became loose and the cable slipped.

Next check the fuel filter to make certain it is clean. This is a maintenance item, so do it any way.

Then check the Mixing elbow.

Although @Ralph Johnstone can get a little testy at times, his heart is in the right place and he is fastidious, when it comes to engine maintenance trust his advice. We all have seen photos of his engine compartment, it is immaculate.

 

[JBS Mystic]

Thank you all for the insightful advice. Once the boat is out of the water, I'll start digging into the engine and transmission, starting with the simplest components. Unfortunately, our marina doesn't permit outside mechanics, so we're dependent on marina's people for anything major. Of course, on a forty year old boat, investing in an engine repair may be foolish given the risk of other components failing.

 

[jssailem]

Things I have learned about my engine rebuild adventure.

• It takes much longer than you might imagine.
• Rebuilding is less costly than a new engine and the associated reengineering of your boat.
• There will be project creep.
• If you rebuild the engine on an old boat, include the transmission, shaft, prop, accompanying seals, and bearings.
• inspect and rebuild the electrical systems while you have the engine out.

 

[Ralph Johnstone]

Once the boat is out of the water, I'll start digging into the engine and transmission,

If possible, it would be better to leave the boat in the water as you will be doing many "engine starts" and require cooling water. If you do find yourself on the hard, you can set up a barrel for a raw water pump suction hose but extreme caution is required otherwise you could wind up with a hydro-lock and blow the head off the engine. At that point, no more decisions about the engine.

As I previously mentioned in post #4, Yanmars are extremely forgiving little beasts. I'm betting you can get yours back on the water for a minimal cost, if you're willing to follow the instructions given here, and in particular, post #4 for the cheapest starters.

Unfortunately, our marina doesn't permit outside mechanics,

And fortunately, you're an inside mechanic.

so we're dependent on marina's people for anything major.

You won't be getting into anything major.

 

[mermike]

Of course, on a forty year old boat, investing in an engine repair may be foolish given the risk of other components failing.

If you feel there's risk, then address it. It's no fun going out in a boat that you're not sure will bring you back.

I've had my 41 year old boat for 6 years now and have addressed most of the major items. There are still some that need to be done. I hope to get to them before the first round of repairs come due again. And they will eventually. Everything but the hull is a consumable.

 

[Project_Mayhem]

you can set up a barrel for a raw water pump suction hose but extreme caution is required otherwise you could wind up with a hydro-lock and blow the head off the engine

Under what conditions can this happen and how can it be avoided when running the engine out of the water?

 

[Ralph Johnstone]

Under what conditions can this happen and how can it be avoided when running the engine out of the water?

Gotta put on your virtual goggles to picture this one :

1. Your boat is on the hard and up on stands.

2. Disconnect the inlet hose to your raw water pump.

3. Attach a sturdy garden hose to this open port of your raw water pump. You MUST use all threaded or barbed fittings of whatever you can cobble together at this connection. It will see a fairly high vacuum when in operation.

4. Throw the open end of the garden hose over the side of the boat so it's laying under the hull.

5. Place a 5 gallon open pail under the hull and place the open end of the garden hose in it.

6. Provide another, separate garden hose which is connected to a hose bib which can supply a strong, continuous flow of tap water into the 5 gallon pail.

7. Turn on the supply hose, fill up the 5 gallon pail, and leave it strongly overflowing.

8. Now comes the tricky part. The raw water pump MAY have problems pulling water all that way up to its suction port so plug the bottom end of the hose, fill with water, re-attach to the raw water pump suction, start the motor and you have a safe, non-pressurized supply of cooling water.

NOTICE: if you cannot think for yourself (as we are seeing more and more often in these SBO pages) DO NOT even consider trying this. You will completely screw up in a brand new fashion which you've never seen the likes of before. This does not include you @Project_Mayhem, as your posts make sense.

The above instructions are purely for demonstrating how this arrangement can provide a safe, unpressurized, supply of cooling water to your raw water pump. There are numerous variables here such as : how much vacuum will be required to lift the water to the pump, will the pump work, will the hose collapse, maybe put the 5 gallon pail on the cockpit floor or on the cabin roof to remove the vacuum As previously mentioned, if you can't tie your own shoes in the morning, don't even look at this.

WHAT HAPPENS IF YOU ATTACH A PRESSURIZED WATER HOSE TO THE RAW WATER PUMP INLET

And then the engine decides to stop on its own.
Water which is under municipal pressure will be :

1. Forced past the raw water pump,
2. Through the heat exchanger,
3. Out the mixing elbow,
4. Into the muffler until it floods (remember the big exhaust loop),
5. Quickly back up into the exhaust manifold,
6. Find an open exhaust valve,
7. Fill a cylinder,
8. And after you've forgotten all this is going on, you attempt to start the engine again and :

Maybe not quite that bad, but you get the idea.

 

[Tally Ho]

I have seen this, and will look for the video, but exactly what Ralph is describing….

A bucket in the cockpit, and a hose from the engine water intake pump. Clamp the hose into the bucket so it won’t fall out. Then take a garden hose and clamp it on the die of the bucket and turn on the water…let the bucket fill (will eventually overflow and drain out of the scuppers. NOW you can start the engine and suck water out of the bucket. Try to match garden hose output to the water pump intake….you don’t want the bucket to run dry.

What would cause hydro lock is if you hooked the garden hose directly to the the water intake pump. This could cause water to flow faster than The water pump is supposed to pump and it could fonce water into the cylinders..

Greg

Found the video…note the additional concern over the height of the bucket vs the siphon break…