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  Topic Review (Newest First)
02-11-2013 02:07 AM
Re: Volvo MD7a

But anyway...I have the same engine. How do you know oil isn't making it up there? I'm assuming you have already checked the dipstick to ensure adequate oil in the pan?
02-11-2013 02:05 AM
Re: Volvo MD7a

Tony...note that this thread was started and the conversations ended almost a year ago. You might have better luck getting an answer by starting a new one.
02-07-2013 12:17 PM
Re: Volvo MD7a

Hi I have a volvo penta md7a and oil isn't reaching the top end, can anyone tell me why.
04-01-2012 06:53 AM
Re: Volvo MD7a

Grand River :

If you have decent compression, and are delivering fuel, the motor really should start reliably and promptly. Remember to use near-full throttle for the starting, then throttle back quickly when the motor starts.

It is not a good idea to use starting fluids (or "narcotics" as we like to call them here) as the motor will get addicted to them and you will need them all the time.

If you have to use narcotics, then you must, but only if you must.
03-30-2012 07:07 AM
Re: Volvo MD7a

I also have a Sabre 28 w/ the MD7A & have spent a bunch of time looking into what's out there for repowering if the need arises. You can get a Yanmar w/ a ZF transmission & this will addresse the LH rotation issue of the Volvos.

Never use starting fluid on a diesel, try WD-40 instead, much safer & it won't destroy the motor.
03-15-2012 10:32 PM
Re: Volvo MD7a

I haven't checked to see if I had an air leak in the be exact, I have never thought that might be the has always acted like that since I bought the boat and I have always just worked around it...I'll have to check it next time I am up to the boat...
03-12-2012 04:27 AM
Re: Volvo MD7a

Fit a 235AD...

Electric Fuel Pumps - Stewart Warner pressurise your fuel system and you will never have an air leak again. If the fuel system leaks, you will see the diesel dripping out and you can fix it.

The motor is sound, and oversize pistons were available from Mahle in 1998 and probably still are. Two pistons will cost about 100 each, and a top end gasket set about another 100. Reboring the two barrels would cost about another 100.

You could re-cut and re-grind the valve seats also.

You don't even have to take the motor out of the boat to do it.
03-11-2012 10:40 AM
Re: Volvo MD7a


Are you sure that you don't have a very small air leak in your fuel system? From the engine's prospective, there is no difference between sitting for a week and 2 weeks. After a day, the engine block will not retain any heat and nothing should change so starting should be the same provided that your batteries are not discharging.

If you want to test for an air leak, let it sit for 2 weeks and pump the hand primer for a long time before trying to start it. If it starts similar to sitting for a week, you have a small air leak. This will not rule out an air leak in the injection line but it will get most of the likely suspects.
03-11-2012 09:21 AM
Re: Volvo MD7a

I have a vintage 78 MD7A in my Newport and I am in a cooler climate (northern Idaho...) so I know of what you speak. Mine cranks quite long if I am starting it after being idle for a couple of weeks...but as long as I crank it over every week it does just great. the key on the MD7A that I found is to make sure your throttle is at least 2/3 forward and if it doesn't catch within about 6-10 seconds, back off and try again. I have had to resort to starting fluid when I have laid her up for over a couple of weeks, but if you use it sparingly, she fires right up. Klem is certainly right about the noise and the vibration...even with new motor mounts she shakes and dances...and a loose engine access hatch adds to the noise. The thing about the old Volvo's is, if the compression is good, they are as dependable as you can get, with very little maintenance. We have several older boats in the marina with D6's and D7's and we all swear by far as heating it up, a crankcase heater (dipstick style) will help if you have shore power.
02-28-2012 12:20 PM
Grand River Raider
Yes there will be shorepower

Originally Posted by klem View Post
Will you have shorepower where you keep it? With it, you can make an engine start much easier through several different methods. The easiest is to aim a heat gun at the air intake for a little while. You could also put an oil pan heater on which helps with cranking speed and does heat the block a little. Another option would be to heat the compartment. With all of these you want to be careful about making it safe. Unfortunately, you can't really hook up a conventional coolant block heater on a raw water cooled engine.
Yep, there would be shorepower and those are some options to consider. Thanks.

I think the bigger issue is simply whether or not the engine as a whole is worth the risk given that it is raw water and has spent its life in saltwater. Especially since on a boat of this vintage, an engine repair/replacement is such a large proportion of the overall cost/financial worth of the boat. I suppose the best that can be done is to have a diesel survey and take a chance if I want to go with this boat.

As mentioned, in a perfect world I would prefer a different engine and it has given me enough pause to consider buying other boats with newer engines. Then I have to keep reminding myself I'm not simply looking to buy an engine.
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