I have a 1980 CD28 powered by a MD7A. Last weekend turning the key on battery 1 produced nothing, notwithstandng the fact that the battery indicator said it was fully charged. Turned to ALL and turned the key: loud awful screetch, then the motor turned over and ran fine. So I went sailing for about three hours. Wind died, turned key and got nothing. Moved to ALL and again an awful screetch and engine started. Went home. Back at dock, turned the engine off, turned it on and it started fine on each individual battery. No screetches.
So the batteries are not the problem. It has been suggested (by non-experts for one, and by a diesel expert who didn't want to get involved in the job for two)that the starter is the problem, and if so this is a larger issue because the starter is tied into the alternator. At the least the starter would have to be removed and rebuilt since parts are no longer available.
Does any reader have any suggestions - diagnoses, recommendations?
Second problem with this engine: There is an oil leak. Small but a leak. Engine mechanic cannot find it, even using mirror underneath engine. Says he will have to pull engine (this winter) to find and close leak. This engine has 20 years but not that many hours. Any thoughts?
(FYI: this really good engine man is out of town until next week, so he has yet to look at the starter problem.)
aewebster@earthlink.net
Volvo MD7A - problems
Moderator: Jim Walsh
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Scott Ritchey
Re: Volvo MD7A - problems
I had an MD7 in my old Columbia. Sometimes I got the no-cranh response which, I think, was caused by sticking brushes in the starter. After tapping the starter with a wrench, it would start normally. In your case I'm not sure. I did not experience the screech you mention. It may or may not be related. Also, the battery switching may have been coincidental. Troubleshooting may be slow unless it happens consistently.
Next time it occurs, see if the battery supports some other electrical load (like cabin lights). Do they dim when you try to crank the motor? If so, look for a weak battery or dirty connection. Next, try just tapping the starter (and solenoid) to free a possible stuck brush (be careful not to short out the battery lead. It may just be that you needed both batteries to engage the bendix/solenoid. If so, look for a weak battery, dirty connections, or maybe a bad starter. With intermittant problems you either spend a lot of money and replace a lot of stuff or you use patience to track the problem to the source.
On the oil leak, check the transmission. On mine, the output shaft (it's more of a drum with gear teeth inside) rusted and cut up the shaft seal. Cost $400 to fix it professionally.
ritcheyvs@aol.com
Next time it occurs, see if the battery supports some other electrical load (like cabin lights). Do they dim when you try to crank the motor? If so, look for a weak battery or dirty connection. Next, try just tapping the starter (and solenoid) to free a possible stuck brush (be careful not to short out the battery lead. It may just be that you needed both batteries to engage the bendix/solenoid. If so, look for a weak battery, dirty connections, or maybe a bad starter. With intermittant problems you either spend a lot of money and replace a lot of stuff or you use patience to track the problem to the source.
On the oil leak, check the transmission. On mine, the output shaft (it's more of a drum with gear teeth inside) rusted and cut up the shaft seal. Cost $400 to fix it professionally.
Ann E Webster wrote: I have a 1980 CD28 powered by a MD7A. Last weekend turning the key on battery 1 produced nothing, notwithstandng the fact that the battery indicator said it was fully charged. Turned to ALL and turned the key: loud awful screetch, then the motor turned over and ran fine. So I went sailing for about three hours. Wind died, turned key and got nothing. Moved to ALL and again an awful screetch and engine started. Went home. Back at dock, turned the engine off, turned it on and it started fine on each individual battery. No screetches.
So the batteries are not the problem. It has been suggested (by non-experts for one, and by a diesel expert who didn't want to get involved in the job for two)that the starter is the problem, and if so this is a larger issue because the starter is tied into the alternator. At the least the starter would have to be removed and rebuilt since parts are no longer available.
Does any reader have any suggestions - diagnoses, recommendations?
Second problem with this engine: There is an oil leak. Small but a leak. Engine mechanic cannot find it, even using mirror underneath engine. Says he will have to pull engine (this winter) to find and close leak. This engine has 20 years but not that many hours. Any thoughts?
(FYI: this really good engine man is out of town until next week, so he has yet to look at the starter problem.)
ritcheyvs@aol.com
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Mark Yashinsky
Re: Volvo MD7A - problems
All the "charge" indicator is, is a voltmeter. It just measures teh number of volts in the system, not the amount of amps that the battery can put out. Like Scott said, turn on a cabin lite and try the starter. If the lite goes out and the starter chatters, the battery is dead, there is a bad connection, etc. If the lite does not go out, then something is hanging in the starter. The noise sounds like the starter is not engaging the flywheel of the engine. To check the battery involves charging it fully, let it rest, then putting it under a heavy load (100+ amps, depending on battery group number) and watching the voltage drop. A couple of ideas, do you do a lot of sailing and very little motoring, are the batteries old, all connections clean and tight, anything discharging the batteries (bilge pump, radio left on, lite left on)???
FYI, a friend has a CD27 that I installed a stereo (head, amp, multiple speakers, etc) on and last weekend, did some sailing, anchored, and went swimming, etc over a number of hours and we were ready to motor off the anchorage, the battery we were on laughed at us. Drained the thing. Went to BOTH, lit the engine up and ran it to recharge. Took a while till could exclusively start on the battery we drained to let it be only one being charged.
FYI, a friend has a CD27 that I installed a stereo (head, amp, multiple speakers, etc) on and last weekend, did some sailing, anchored, and went swimming, etc over a number of hours and we were ready to motor off the anchorage, the battery we were on laughed at us. Drained the thing. Went to BOTH, lit the engine up and ran it to recharge. Took a while till could exclusively start on the battery we drained to let it be only one being charged.
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Larry DeMers
Re: Volvo MD7A - problems
Sounds to me like the starter is having a problem. Define the screeching sound a little more please. Ideas;
1. Loss of a tooth on the flywheel gear ring that mates with the starter. If the starter is asked to start the engine, but the missing teeth on the flywheel line up with the starter, the bendix gear in the starter will eject out trying to engage the flywheel, but will encounter only ground teeth..metal. This could result in a grinding sound, but why it would behave differently with 2 batteries is a question.
2. Starter truly is having problems, probably frozen or shot bearings (happens all the time). The starter "drags" when trying to start, drawing a lot more current. The battery is probably in so-so condition, and gets drawn down too far to turn the starter/engine over. Combining your battery banks provides more current, which works.
The screeching sound? In this scenario it would be the alternator trying to put 50 amps back into the battery banks, which puts a tremndous load on the belt, which if loose, will squeal like heck! Your alternator may not be quite tight enough in it's belt adjustment, so under high output from the alternator, it locks up, and the belt screeches.
3. (Maybe) Another cause of a hard turning starter is that the load on the starter is too high, locking up the alternator, making the belt squeal. One thing that can do this is hydrolock of the cylinders (I really hope this is not the case). Hydrolock of the cylinders happens when water gets into the cylinder (s), locking them because water cannot be compressed. Continually trying to start the engine will force the water out the exhaust valve eventually (if leaky, as most are to some extent), allowing the engine to turn over eventually. Now this is a far fetched possibility that requires some rather odd things to be wrong with the engine, so I would not consider it too seriously yet. But hte danger is that if the engine should fire on one cylinder while still hydrolocked in the other, you can pretty much total your engine out. It bends connecting rods, and really breaks stuff. Hope this is not involved here.
But it does sound like there are a few small things needing attention on this engine, and the symptoms are hiding them a bit.
Let us know what you found please..interesting problem.
Cheers!
Larry DeMers
s/v DeLaMer
Cape Dory 30 ~~~~Sailing Lake Superior~~~~
demers@sgi.com
1. Loss of a tooth on the flywheel gear ring that mates with the starter. If the starter is asked to start the engine, but the missing teeth on the flywheel line up with the starter, the bendix gear in the starter will eject out trying to engage the flywheel, but will encounter only ground teeth..metal. This could result in a grinding sound, but why it would behave differently with 2 batteries is a question.
2. Starter truly is having problems, probably frozen or shot bearings (happens all the time). The starter "drags" when trying to start, drawing a lot more current. The battery is probably in so-so condition, and gets drawn down too far to turn the starter/engine over. Combining your battery banks provides more current, which works.
The screeching sound? In this scenario it would be the alternator trying to put 50 amps back into the battery banks, which puts a tremndous load on the belt, which if loose, will squeal like heck! Your alternator may not be quite tight enough in it's belt adjustment, so under high output from the alternator, it locks up, and the belt screeches.
3. (Maybe) Another cause of a hard turning starter is that the load on the starter is too high, locking up the alternator, making the belt squeal. One thing that can do this is hydrolock of the cylinders (I really hope this is not the case). Hydrolock of the cylinders happens when water gets into the cylinder (s), locking them because water cannot be compressed. Continually trying to start the engine will force the water out the exhaust valve eventually (if leaky, as most are to some extent), allowing the engine to turn over eventually. Now this is a far fetched possibility that requires some rather odd things to be wrong with the engine, so I would not consider it too seriously yet. But hte danger is that if the engine should fire on one cylinder while still hydrolocked in the other, you can pretty much total your engine out. It bends connecting rods, and really breaks stuff. Hope this is not involved here.
But it does sound like there are a few small things needing attention on this engine, and the symptoms are hiding them a bit.
Let us know what you found please..interesting problem.
Cheers!
Larry DeMers
s/v DeLaMer
Cape Dory 30 ~~~~Sailing Lake Superior~~~~
Ann E Webster wrote: I have a 1980 CD28 powered by a MD7A. Last weekend turning the key on battery 1 produced nothing, notwithstandng the fact that the battery indicator said it was fully charged. Turned to ALL and turned the key: loud awful screetch, then the motor turned over and ran fine. So I went sailing for about three hours. Wind died, turned key and got nothing. Moved to ALL and again an awful screetch and engine started. Went home. Back at dock, turned the engine off, turned it on and it started fine on each individual battery. No screetches.
So the batteries are not the problem. It has been suggested (by non-experts for one, and by a diesel expert who didn't want to get involved in the job for two)that the starter is the problem, and if so this is a larger issue because the starter is tied into the alternator. At the least the starter would have to be removed and rebuilt since parts are no longer available.
Does any reader have any suggestions - diagnoses, recommendations?
Second problem with this engine: There is an oil leak. Small but a leak. Engine mechanic cannot find it, even using mirror underneath engine. Says he will have to pull engine (this winter) to find and close leak. This engine has 20 years but not that many hours. Any thoughts?
(FYI: this really good engine man is out of town until next week, so he has yet to look at the starter problem.)
demers@sgi.com
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mike
Re: Volvo MD7A - problems
I'd check and see if flywheel or starter/alternator pulleys are rubbing metal somehow. Had that noise on a Westsail32 we owned and a simple adjustment fixed it.
Regarding the oil leak, one response said a $400 bill to fix. I expect to remove and reinstall the engine would mean a whole lot more than that would be involved costwise. You indicated it was a "slow" leak. With that in mind, I'd tighten a few things, make sure oil filter and such were tight (not too tight though). And if the leak continues despite those efforts, I'd be sorely tempted to let it continue. Merely put a pan to catch it and discard it periodically. Probably save you $1500 or so.
Mike
michaelconniesmith@home.com
Regarding the oil leak, one response said a $400 bill to fix. I expect to remove and reinstall the engine would mean a whole lot more than that would be involved costwise. You indicated it was a "slow" leak. With that in mind, I'd tighten a few things, make sure oil filter and such were tight (not too tight though). And if the leak continues despite those efforts, I'd be sorely tempted to let it continue. Merely put a pan to catch it and discard it periodically. Probably save you $1500 or so.
Mike
michaelconniesmith@home.com