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kentg 09-10-2010 09:10 PM

Bahama 30 exhaust
I will be repowering sometime in the future, the MD-7A is getting tired. I have problems with exhaust fumes coming into the cockpit unless we leave the forward dodger window out. Has anyone ran the exhaust out the side of the hull instead of the transom?


newhaul 09-12-2010 12:55 AM

yes ive done it on a couple of sailboats the most important part is to ensure the outlet is above the water line when heeled over. what engine were you thinking of installing. or just rebuilding existing volvo?

kentg 09-12-2010 01:11 PM

since it is raw water cooled and has been in the salt water all it's life, a new one is in order. Probably a yanmar as it has the closest footprint to the MD-7A.

huguley3 09-12-2010 01:44 PM

I was looking at the Beta when I was considering a new engine. They are really nice for the money. Looked at them at the Miami boat show last year and it seemed really well thought out. My MD7b is still churning along so I have not had to do it.

kentg 09-13-2010 07:18 AM

I am on the other coast! At the seattle boat show the Beta was quite a bit more expensive than anything else, the sales rep even said so!

dacap06 09-19-2010 07:33 PM

Yanmar is a tight fit
Kent, your plan appears sound but I have some cautions.

About Yanmar ... my '84 IB30 came with a Yanmar 2GMF - 13 HP continuous output. I think it was the standard engine for that year. It's a great engine -- it runs fabulously, does not burn oil, and its compression is still good a quarter century later. At my survey it started with 2 seconds of cranking after 2 years on the hard. In cold weather it starts after only a few seconds of cranking if I set it to 1/2 throttle.

However, there is a drawback. The 2GMF is a very tight fit! After I change the big Racor filter, I can't bleed the fuel line using the fuel lift pump w/o burning my arm when the engine is hot. I hope the newer Yanmar models you will be considering are smaller and better arranged. Be careful and thorough doing the research to ensure the new engine will fit.

I have also wished I had a little more horsepower when pushing upwind in some chop. If the rule of thumb is 2 HP per 1000 lb, my boat should have a 17 HP continuous output engine. Even now Yanmar offers models around 14 and 21 HP but not one in between. Finding something with that rating is possible. I see that Westerbeke offers the 18 HP model 20B2 (see I've no idea how good the engine is or how easy it is to service, so don't take my mention as an endorsement. But if I were doing the research the 20B2 would be on my short list of engines to look at closely.


kentg 09-20-2010 06:56 AM

Tom thanks for the heads up. Because you have the stock engine, assume you still have the exhaust out the transom?

That is the real question I have, about placement if moving it to the side of the hull.


dacap06 09-20-2010 09:15 PM


Originally Posted by kentg (Post 645833)
Tom thanks for the heads up. Because you have the stock engine, assume you still have the exhaust out the transom?

That is the real question I have, about placement if moving it to the side of the hull.


Yes, my exhaust is still out the transom. It comes out about 4" above the static waterline, and of course it has a big loop to prevent backflooding should a wave impact the stern.

I'm not sure about moving the exhaust to the transom either. To keep the line from backfilling when heeled you'd want it high up on the quarter, but if you mount it high up then some wind angles will blow the exhaust back into the cockpit. Not pleasant. The exit point could also impact your ability to store stuff in your lazarette so it doesn't bump the exhaust hose or the water muffler.


spillarc 10-13-2010 05:04 PM

IB 30 Repower

Just to throw in my 2 cents, thought I would share my recent repower experience. I repowered my 83' Islander Bahama 30 this year with a Beta 16 after a good deal of research on models from the major diesel manufacturers.

Both Yanmar and Beta (Kubota based) have models that have mounting dimensions pretty close to the Volvo MD-7A. The Yanmar is a great engine too, but I chose the Beta because for a little less money I got more Hp (16 vs. 14) and I really love the serviceability of the Beta. I've been able to go to the Kubota tractor dealer and purchase oil filters, fuel filters etc..., and the built-in oil pump makes oil changes a snap. I considered also going with a 20Hp from both Yanmar and Beta, but after talking to Beta they convinced me that the 16 Hp model was more than adequate. I don't regret my choice as I have plenty of power now and the engine is very economical to run. I think the real advantage of going to the 20Hp models is they may run a little smoother as they have 3 cylinders vs. 2 cylinders.

The install did involve raising the engine mounts and a new shaft was required as well. It also required a new prop (needed one anyway) as the Volvo turns the prop CCW in the forward gear, the Beta and most others are CW.

You'll find the new diesels are almost half the weight of the Volvo for nearly the same Hp. The Beta runs very clean and diesel fumes seem nonexistent. However, I do miss the Volvo's big flywheel when at idle as it did a good job of smoothing things out. The Beta is smoother when at power though, and I just don't leave it at power for long at idle.

Good luck if and when you decide to do your repower.

kentg 10-14-2010 06:54 AM

thanks for your 2 cents, worth more than that probably! The Seattle boat show is coming up in a few months, so I will be looking a lot closer there, and will definitely get some quotes!

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