I need expert diesel engine help

[thoranfly]

I need expert help. I am relatively mechanically inclined, but the problems I am experiencing have be baffled. I have an '85 Universal M25 with an Oberdorfer sea water pump.

Mon, Jun 3, 2013- After work, go out to my Catalina30 in the mooring field, start her up without incident and motor into a slip for some seasonal cleanup and the oberdorfer water pump impeller change at the 2 year mark. Changed impeller (impeller was worn, but no broken pieces), started the engine, checked for leaks (none found) and checked for water being pumped out aft of the boat (water was being pumped out).

Tue, Jun 4, 2013- Out to the boat for some cleanup, run the A/C with shore power. Try to start the engine...nothing! No clicking of the solenoid, no turning of the motor. all guages reading normal, both batteries test good. Both of them only 30 days old. Friend suggests I try a "hotwire" start to test the solenoid. I ran a line directly from the battery to the solenoid...and the engine starts without issue as if it were brand new. I shut it down and tried to do a normal start with the starter button and it starts again as if new. I started the engine normally and ran it 3 or 4 times thoughout the day. Never a problem, to include water pump working normally.

Wed, Jun 5, 2013- Out to the boat, tried a normal start....nothing. Tried the "hotwire" start, started right up. Shut it down, tried a normal start, started right up.....again, using normal start 3 or 4 times throughout a 3 hour period, started normally as if it were new. But now a new wrinkle: no water being pumped over board from the oberdorfer impeller.

Thurs, Jun 6, 2013- Out to the boat for some diagnostic work. Tried normal start: nothing. Tried "hotwire" start: motor turns, but now won't start. Tried normal start: motor turns, but won't start. Back to "hotwire" start: nothing. No clicking, no turning. Back to normal start: nothing! Both batteries still test good.

Anyone have any ideas? ...other than shooting it and putting it out of my misery. I've owned the boat for 5 years, never a problem like this.

 

[Patrick S/V Shangra-La]

When you repeatedly tried to start the motor did you close the seacock for the raw water pump. Too much trying and you can fill the motor with water as there is no exhaust to push raw water out of the muffler.

When it ran with no water coming out was there something blocking the water intake? These are the only 2 things I can think of. Also if you push the starter button and nothing, but can jump at the starter...Replace the starter button.

 

[rbmcintire]

When you repeatedly tried to start the motor did you close the seacock for the raw water pump. Too much trying and you can fill the motor with water as there is no exhaust to push raw water out of the muffler.

When it ran with no water coming out was there something blocking the water intake? These are the only 2 things I can think of. Also if you push the starter button and nothing, but can jump at the starter...Replace the starter button.

I agree. Drain the AquaLift Muffler at the petcock on its base. The engine can't start if the exhaust gases can't flow out. If the water level in the muffler, blocks the outlet tube, you're stopped.

The intermittent electrical issue in your starting circuit is a bad connection. Trace it through. It's likely at a point where the wires land on a device or where they connect at a junction. Disconnect, clean w/ sandcloth the wire terminals at the starter, alternator, and battery switch. Reconnect. Go thru all the wires and do that. Replace the key switch and/ or starter button if they are original. A new battery switch might even be a worthwhile preventive maintenance measure. Getting at the wires behind the engine panel in the cockpit means those connections also get cleaned off. If you have the "trailer plug" connections at the engine or engine panel, re-connect those with new means (new Duetsch plugs, marine-grade butt connectors or adding terminal blocks) With the existing new batteries and new tight wire connections, you're all set.

Oh yeah, except now with the engine starting perfectly each time, you might still have to work on why it's overheating.

Rob

 

[JK_Boston_Catalina310]

I agree with rbmcintire, I think the starting issue is an electrical connection. I would add to his list to check the grounds. And when you check these connections you have to actually touch each connectiona and pulll on them. I had a similar issue last year and it was a connection that looked fine but ended up being bad and I wouldn't have found it without pulling on the connection.

As said above, drain the aqualift muffler. Once you get that figured out you might have an issue with your raw water still. You might have to check the strainer or take off the exhaust elbow to inspect if it has scaling that is preventing flow.

Good luck,

Jesse

 

[anchorclanker]

Lacking a waterlogged muffler as suggested above, your symptoms point directly at the starter motor itself. Try lightly tapping the side of the starter with a hammer as you turn the key (may need a helper). Likely the brushes are sticking or worn which is causing the intermittent problem, higher current need, and slow cranking.

 

[Donnybrook]

You should have a yellow and red wire going to the starter. Trace it down and find the inline fuse. These are famous for getting dirty and oily and not making good connection.

 

[Acoryboston]

Don't know if you've solved your engine woes, but just in case, I thought I'd weigh in. When working on a daysail schooner out of Mystic CT we had similar issues of intermittent starting problems and trouble with raw water flow. The confusing thing was that it would work sometimes and not others.

The issue for us was that a new impeller had been installed backwards and was working only sporadically. Everything else was fine. You mentioned that your troubles started after you changed the impeller so I thought I'd share our similarly confounding experience for what it's worth. The good news was that it was a no-cost fix! Good luck.

 

[Stu Jackson]

Two things:

1. Oberdorfer faceplates MUST be absolutely flat. Sometimes they build up deposits that stop flow. Either sand it down or buy a new one.

2. No start: try our Critical Upgrades topic and our C34 Tech wiki with tons of M25 engine information. Check the fuseholder cleverly hidden underneath your alternator.

http://c34.org/bbs/index.php/topic,5078.0.html

http://www.c34.org/wiki/index.php?title=Diesel_Engine

 

[Nom De Guerre]

Two things:

1. Oberdorfer faceplates MUST be absolutely flat. Sometimes they build up deposits that stop flow. Either sand it down or buy a new one.

2. No start: try our Critical Upgrades topic and our C34 Tech wiki with tons of M25 engine information. Check the fuseholder cleverly hidden underneath your alternator.

http://c34.org/bbs/index.php/topic,5078.0.html

http://www.c34.org/wiki/index.php?title=Diesel_Engine

It probably doesn't make a difference, but I've always used a full box cutter blade to scrape a faceplate clean/flat, rather than sand it. I've always felt like it's more likely to uniformly resurface the plate/remove any residue.

Theory being that a hard deposit won't sand off well without sanding down surrounding material.

 

[foolproof]

While you're checking connections, look closely at the stripped wire ends where they fit into terminals, butt splices, etc. Often times corrosion will build up on the wire and create too much resistance, and cause some of the problems you are describing. Also, pull connectors apart as necessary to check for corrosion on the connectors i.e. knife or handshake connectors...they are prone to corrosion as well.

 

[Jack - La Paz Mx]

When we bought our '83 Catalina in '95, it started right up. After a week we had the exact same symptoms. Then, even though panel meters showed voltage, when we hit the starter, nothing. Voltage measurements showed batteries were fine. Turned out to the the common ground connection on the port side of the engine block. Apparently it would pass low voltage, but the demands of the starter would not pass through the crappy connection. Tightening the nut/bolt fixed it, but removal, cleaning, and tightening fixed it permanently. Easy thing to test, put a wrench/socket on the major high current connections on batteries, 1, 2, all switch, and grounds.

Comments relative to cranking engine without starting are valid and you should check for water in the cylinders and a full aqualift muffler. Always shut through hull when cranking engine without starting.