The 3GM-34 Yanmar Diesel in our Hunter 37 has required that I use the compression release several times of late to start. in the 3 seasons that we've owned it, I've had to do this when it has sat without use for several weeks, but recently it requires it even when it has not been shut down for long, twice when starting up after a few hours of sailing. The engine starts and runs fine when the compression release is used. there are no other indications of a problem (overheating, exhaust smoke, rough idle, etc) A couple of questions from someone who is a Diesel neophyte: 1. Is this an indication of the engine needing attention (injectors, battery...)? 2. Is there something that I could be doing on shutdown that will avoid this? 3. If this is normal operation, why isn't there a compression release at the engine panel vice requiring two people to complete the start process (one at the helm, and one below, in the galley holding and releasing the compression release)? Has anyone added a compression release cable at the helm? How difficult is this? Thanks for your help.
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What is the condition of your batteries?
Ken: What is the condition of your batteries? I would start there. The starter requires a lot of amperage to crank the engine. Even if your batteries seem to be good, I would have them load tested.
Ken: What is the condition of your batteries? I would start there. The starter requires a lot of amperage to crank the engine. Even if your batteries seem to be good, I would have them load tested.
B
Bob
Steve Sound Correct
I agree with Steve that the problem is with the batteries and suggest that you either replace the battery or at least have it "load tested".
I agree with Steve that the problem is with the batteries and suggest that you either replace the battery or at least have it "load tested".
Not normal
It is not normal to have to use the compression release to start a diesel engine. Like the others have already said, get you battery checked out using a load test. They can use an hand held instrument to do a load test. Unless you really know how a diesel engine works, I would suggest you spend a few bucks and get a local Yanmar diesel mechanic to come out, and give the engine an once over. Maybe you can video tape the mechanic and have him explain to you what he is doing. A good reference for your own future maintenance tasks.
It is not normal to have to use the compression release to start a diesel engine. Like the others have already said, get you battery checked out using a load test. They can use an hand held instrument to do a load test. Unless you really know how a diesel engine works, I would suggest you spend a few bucks and get a local Yanmar diesel mechanic to come out, and give the engine an once over. Maybe you can video tape the mechanic and have him explain to you what he is doing. A good reference for your own future maintenance tasks.
K
Ken Bell
Thanks
Gentlemen, Thanks for the help. I hadn't initially suspected the batteries because they're only 2 seasons old and have had minimal usage which would have degraded their life. I'll get a load test done and replace as necesary. Thanks again, ken
Gentlemen, Thanks for the help. I hadn't initially suspected the batteries because they're only 2 seasons old and have had minimal usage which would have degraded their life. I'll get a load test done and replace as necesary. Thanks again, ken
What happens when you turn the key?
What is the result when you try to start without the CR? does it fail to crank?-- Likely the battery or corrosion on cables or a cable problem. If it turns over vigorously, but does not start your problem is not the battery, but elsewhere-- compression, injectors, etc. Let me know what the symptoms are, and I'll give you more direction. ex-USCG Machinery Technician--MK
What is the result when you try to start without the CR? does it fail to crank?-- Likely the battery or corrosion on cables or a cable problem. If it turns over vigorously, but does not start your problem is not the battery, but elsewhere-- compression, injectors, etc. Let me know what the symptoms are, and I'll give you more direction. ex-USCG Machinery Technician--MK
K
KenABell
It Doesn't Crank
It doesn't crank. When it does start succesfully (without the compression release), it fires on the first revolution (or so it seems). If it doesn't fire that quickly then it locks up and you have to go the compression release route. With the compression release, it fires up as soon as you let it go. I'll check out the electrics as soon as I get back down to it. I'm a little concerned about the charging system too. Although most indications are that the batteries aren't holding a charge, it may be that they aren't getting fully charged. Either way - it appears that a bettery load test needs to be the next step. Thanks for your help. Ken
It doesn't crank. When it does start succesfully (without the compression release), it fires on the first revolution (or so it seems). If it doesn't fire that quickly then it locks up and you have to go the compression release route. With the compression release, it fires up as soon as you let it go. I'll check out the electrics as soon as I get back down to it. I'm a little concerned about the charging system too. Although most indications are that the batteries aren't holding a charge, it may be that they aren't getting fully charged. Either way - it appears that a bettery load test needs to be the next step. Thanks for your help. Ken
Definitely electrical
Your problem is electrical. Start with batteries. Check cable ends for corrosion. I have seen corrosion on the ground cable at the engine connection be the culprit. Check cables for continuity--broken or frayed strands can result from engine vibration-- especially if wrong type of cable used ie too few strands that make up wire. What type of batts? If wet cell do you check and fill water regularly? If AGM or Gel- do you have the right charger-- a "normal" wet cell charger will cook AGM's as they have a lower charging voltage than wet cells. Good luck!
Your problem is electrical. Start with batteries. Check cable ends for corrosion. I have seen corrosion on the ground cable at the engine connection be the culprit. Check cables for continuity--broken or frayed strands can result from engine vibration-- especially if wrong type of cable used ie too few strands that make up wire. What type of batts? If wet cell do you check and fill water regularly? If AGM or Gel- do you have the right charger-- a "normal" wet cell charger will cook AGM's as they have a lower charging voltage than wet cells. Good luck!
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