My boat is a 1985 Catalina 30 with its original Atomic M25 3cyl diesel. The meter reads 1997 hours.
I bought the boat last year cheap because it had been neglected during Covid. The PO disclosed the blown head gasket. I hired a professional diesel mechanic to rebuild the top of the motor. Now it pushes the boat to six knots at full throttle with ease and I usually motor at ¾ throttle or less. The specs indicate a max rpm of 2500, but my motor’s full throttle reads 1900 on my tach. We checked connections during the rebuild and everything appeared normal. The mechanic thought it would probably pick up after being run for a while. I have run it for about 150 hours, and the motor keeps running quieter and smoother, but there is no increase in rpm's. I don’t know if the tach is accurate, but the motor seems excellent. After 100 hours, we re-torqued the head and adjusted the valve clearance to the specs in the manual. I only mention this because of the glow plug irregularities.
To start the motor--when connected to the shore power--I have to hold the glow plug switch for 30 seconds before cranking the engine. Now here is the irregularity: The motor likes to start with the glow plug switch depressed and is practically impossible to start without depressing the switch, both while it is cranking and as it starts--after the key is released. After the 30 seconds of glow plug and cranking for 2 or 3 seconds with the glow plugs on, the motor will start to sputter. Releasing the glow plug switch will cause the motor to stall, while depressing it from 5 to 25 seconds longer will start the motor. It will roar to life and there is no smoke or excess vapor, and it runs perfectly after a short warm up.
I have never had to hold a glow plug switch while cranking a diesel before this motor.
We motor out for about 25 minutes. Then after sailing for a few hours, restarting the motor is the challenge. I can't start it without engaging the glow plugs for 20-30 seconds. (Other diesels I have had would not need the glow plugs when the motor was warm) When I get lucky, I can hold the glow plug switch for about 20 seconds, and then the motor starts. Some times it will not start on the first try, and I have to use more glow plug to restart the motor.
When I am unlucky, the motor doesn’t start because the batteries have been depleted.
I have two banks of batteries with a “1-Both-2-Off” switch. Both banks have two group 27 DC batteries--four in total--all the same model. Bank 1 is two years old, and Bank 2 is newer. The onboard charger is Xantax Truecharge2 40a, which seems to be operating correctly.
When connected to shore power for the initial startup, and while motoring out, the switch is on "Both". When we start sailing, I switch to battery Bank 1. If Bank 1 fails upon restart a few hours later, I switch to Bank 2 which usually, but not always, works. There have been a couple of times when I needed a portable jump start to boost the power. The extra glow plug is depleting the power.
I do not run any electrical devices during sailing. I also have used my multimeter to check the charging while motoring, and it reads high 13’s or low 14’s. The alternator was rebuilt and seems fine. I thought four batteries was overkill, but we are cruisers and don't mind a little extra ballast.
My question is why do I have to use the glow plugs to restart, and is this normal? I am planning an overnight with no shore power and am not comfortable with the current batteries.
If I can't fix this problem, I have to improve my starting power. I was looking at AGM batteries with 950CCA. I think one for each bank should be more than enough power. My motor is only a 3cyl 21hp .
I am hoping to add a couple of solar panels to my bimini, but that is a few months away, and I have 5 weeks before the scheduled overnight.
To troubleshoot, we put a meter on each of the three glow plugs and they all read 10.5V We thought that was low and maybe there was a wiring issue, but upon consulting the Atomic manual that came with the boat, 10.5 is correct.
Each of the four batteries reads between 12.3 and 12.7 v when disconnected from the shore power. But I do not have the correct device to check the amps.
Does the 1900 instead of 2500 rpm indicate anything that would necessitate the glow plugs to restart?
Has anyone used AGM batteries for house/starting in a similar sailboat? I am pretty sure that mixing AGM and standard batteries on the same system is a bad idea, so I am open to all new batteries.
Any thoughts would be appreciated
I bought the boat last year cheap because it had been neglected during Covid. The PO disclosed the blown head gasket. I hired a professional diesel mechanic to rebuild the top of the motor. Now it pushes the boat to six knots at full throttle with ease and I usually motor at ¾ throttle or less. The specs indicate a max rpm of 2500, but my motor’s full throttle reads 1900 on my tach. We checked connections during the rebuild and everything appeared normal. The mechanic thought it would probably pick up after being run for a while. I have run it for about 150 hours, and the motor keeps running quieter and smoother, but there is no increase in rpm's. I don’t know if the tach is accurate, but the motor seems excellent. After 100 hours, we re-torqued the head and adjusted the valve clearance to the specs in the manual. I only mention this because of the glow plug irregularities.
To start the motor--when connected to the shore power--I have to hold the glow plug switch for 30 seconds before cranking the engine. Now here is the irregularity: The motor likes to start with the glow plug switch depressed and is practically impossible to start without depressing the switch, both while it is cranking and as it starts--after the key is released. After the 30 seconds of glow plug and cranking for 2 or 3 seconds with the glow plugs on, the motor will start to sputter. Releasing the glow plug switch will cause the motor to stall, while depressing it from 5 to 25 seconds longer will start the motor. It will roar to life and there is no smoke or excess vapor, and it runs perfectly after a short warm up.
I have never had to hold a glow plug switch while cranking a diesel before this motor.
We motor out for about 25 minutes. Then after sailing for a few hours, restarting the motor is the challenge. I can't start it without engaging the glow plugs for 20-30 seconds. (Other diesels I have had would not need the glow plugs when the motor was warm) When I get lucky, I can hold the glow plug switch for about 20 seconds, and then the motor starts. Some times it will not start on the first try, and I have to use more glow plug to restart the motor.
When I am unlucky, the motor doesn’t start because the batteries have been depleted.
I have two banks of batteries with a “1-Both-2-Off” switch. Both banks have two group 27 DC batteries--four in total--all the same model. Bank 1 is two years old, and Bank 2 is newer. The onboard charger is Xantax Truecharge2 40a, which seems to be operating correctly.
When connected to shore power for the initial startup, and while motoring out, the switch is on "Both". When we start sailing, I switch to battery Bank 1. If Bank 1 fails upon restart a few hours later, I switch to Bank 2 which usually, but not always, works. There have been a couple of times when I needed a portable jump start to boost the power. The extra glow plug is depleting the power.
I do not run any electrical devices during sailing. I also have used my multimeter to check the charging while motoring, and it reads high 13’s or low 14’s. The alternator was rebuilt and seems fine. I thought four batteries was overkill, but we are cruisers and don't mind a little extra ballast.
My question is why do I have to use the glow plugs to restart, and is this normal? I am planning an overnight with no shore power and am not comfortable with the current batteries.
If I can't fix this problem, I have to improve my starting power. I was looking at AGM batteries with 950CCA. I think one for each bank should be more than enough power. My motor is only a 3cyl 21hp .
I am hoping to add a couple of solar panels to my bimini, but that is a few months away, and I have 5 weeks before the scheduled overnight.
To troubleshoot, we put a meter on each of the three glow plugs and they all read 10.5V We thought that was low and maybe there was a wiring issue, but upon consulting the Atomic manual that came with the boat, 10.5 is correct.
Each of the four batteries reads between 12.3 and 12.7 v when disconnected from the shore power. But I do not have the correct device to check the amps.
Does the 1900 instead of 2500 rpm indicate anything that would necessitate the glow plugs to restart?
Has anyone used AGM batteries for house/starting in a similar sailboat? I am pretty sure that mixing AGM and standard batteries on the same system is a bad idea, so I am open to all new batteries.
Any thoughts would be appreciated
This includes a link to the Critical Upgrades topic which has more engine information please read it too.
