Volvo MD7 a

[Doc Wheeler]

This summer I picked up a Volvo penta MD7a 2 cyl and a MD6a basket case.. I got the tranny with the better MD&a in hopes of locating a
boat with bad Atomic4 for cheap.. Person Triton or older glass hull.

*I haven't fired it up.. but I do kick over the cyl's every weekend

My current sailboat is a Coronado 23 with outboard..

Will the 13HP Volvo be good for say a 30Ft sailboat?

Doc~

[never monday]

Are you saying you can turn it over by hand?

[Doc Wheeler]

Yea.. the starter didn't come with it.. *Guess it sells for gold-
but you have a compression release, and can spin the cyl's easy
then close the compression and WAMM!

Raw water intake.. I'm thinking of plumbing it to a 55 gal barrel
and run the diesel out of a can..

I got the manual.. but never saw it run-
It's real cool..

[Steve Rust]

I have a MD 7B very similar but a little more power at 17 hp. There is a fitting on the front for a hand crank so try and track one down if it did not come with the engine. As you said with the compression release it is easy to spin although I have a starter on mine it's nice to know that if it fails the engine will still start easily.

[Doc Wheeler]

Right.. *I think I can fab a crank easier than finding one..
I'd make it so that it would kick out.. if God forbid it bucked
back like a Model T..

The starter is $900.. worth more than the "Lump"...
I have everything else and a basket case MD6a for spares..

I'm thinking Alberg 30 to Islander 32 is tops for size on a MD7A?

Doc~

[Steve Rust]

Doc
The crank is designed to slip out and does not lock in. Next time I go to the boat I can take a photo of mine and send it along. Remind me in a week or two if I have not made the trip yet.
I think it would be adequate for a 30 foot boat, others may disagree. It seems more horsepower is needed these days than in the past. Maybe the water is getting thicker.

[cooper]

If its a "good" 13 HP you will probably be fine, that means well matched prop, clean bottom, good fuel and not to much lumpy stuff. Hand cranking these guys can be a great way to save gym membership. A can of start you bastard, may become a friend. With the two cyclinder motors, you only operate on one, leaving the compression lever open on the other until the first starts to fire. Finally throwing it in. It does help to have a friend to throw the lever, because that way you can keep both hands on the crank and 'Pull" it through the compression stroke. (Somtimes this is the difference between start and not) If it has a cold start facility, usually a little button that you press or in later models, you push the throttle? all the way open and release. I have generated much warmth and blisters in the past. As a result I stuck a Briggs and Stratton starter on my geriatric thumper. Like any hand cranked engine of this kind, they CAN miss fire backwards. There is no question, be carefull and aware, (dont try doing it pissed) or you will end up with a broken wrist.

[delmarrey]

Westerbeke Corporation suggests 2 hp for every 1,000 lb of displacement for coastal cruising, and 2.5 hp per 1,000 lb of displacement for offshore.

Personally, I'm running a little over 3 hp per 1K#. But the motor is a light duty motor unlike full time marine motors. The main goal it to reach hull speed at 2/3 to 3/4 max RPM's.

An old Pearson or Alburg 30' will displace around 8500 to 9000#, so at 2HP per 1K =17 to 18 HP. I would say the Volvo is on the light side for a boat that size.

[viking69]

I have a md7a in a newport30 and it ok in normal situations but i have had times where everything is against me and would like a few more horsepower. i am going to convert to a 22hp motor later this year.

[GordMay]

Originally Posted by delmarrey

Personally, I'm running a little over 3 hp per 1K#. But the motor is a light duty motor unlike full time marine motors. The main goal it to reach hull speed at 2/3 to 3/4 max RPM's.
An old Pearson or Alburg 30' will displace around 8500 to 9000#, so at 2HP per 1K =17 to 18 HP. I would say the Volvo is on the light side for a boat that size.

Most Pearson Tritons (28.5' LOA, 6,930# Dry) were delivered with Universal Atomic 4 (30 HP @ 3500 RPM WOT) gasoline auxiliary engines, which produced about 18 HP @ 2250 RPM (75% WOT).
This works out to 2.6 HP per 1,000 Lb DRY Displacement.

Another Carl A. Alberg design, the Alberg 30 (30.25' LOA, 9,000# Dry) also came with the Atomic 4(or the earlier 22 HP Grey “Sea Scout”);
This works out to 2HP per 1,000 Lb. DRY Displacement.

Neither of these were (even then) considered “overpowered” set-ups.

Accordingly, I’d agree that a 13 HP engine is on the “light” side of adequate cruising power for most older 30 Footers.

Remember, most HP/Displ. calculations utilize “Propeller Horsepower”, which might be as low as ½ Brake (Engine) HP.

[Fishspearit]

My Allied Seawind 30 had a similiar engine, the volvo MD 2B, which was rated at 25 hp. I'm thinking that half the horsepower would have been a little disappointing. I'm not sure the differences between the 7A and 2B, but from the way you describe it I imagine it also has the seperate engine block for each cylinder, so that they can be rebuilt individually. While I was lucky and never had a starter problem during the 7 years I used the engine, I remember the issue coming up about the ridiculous cost of a replacement because the starter needs to rotate in the opposite direction of convention. Before the internet, I was told by old timers that there were some car starters that would work if you scoured the junk yards and could find one. Hopefully with all our information connectivity now somebody can source a reverse starter for you at a little better price than Volvo.

[never monday]

MD7 and MD2 are night and day different.

The MD7 came installed in many 7-9K boats. The Islander 30 is the first to come to mind.

[Fishspearit]

Originally Posted by never monday

MD7 and MD2 are night and day different.

Is the reason for a thousand dollar starter the same?

[never monday]

Originally Posted by Fishspearit

Is the reason for a thousand dollar starter the same?

Yes, they are both really old and availability of parts is limited.

[Doc Wheeler]

Wow! excellent information and resources! THANKS!

I picked up the MD7a and basket case just to wise me up
in prepareing for the next boat.. *In my opinion.. it will
be a dated project boat with a stuck engine. I'm looking
on CL in SF Bay on up to Puget sound.

Cleaning up a yard queen sold for back rent.. and converted
to diesel could be a nice stepping stone in the sport

*I'm headed to one of the boats listed in "20 affordible boats
to take you anywhere" ..and that means SE Alaska to Baja
10 years ahead..

Doc~
55 PDX