• From: Nova Scotia
  • Registered: 2010-07-28
  • Posts: 19

Topic: New Engine NEED ADVICE please

Hi
In the past I have seen many Contessa owners re power with the Yanmar 1GM10.  There are other engines as well, however my question is about Engine cooling.

I have a new Yanmar and am about to have it installed; The marine mechanic and many others are not keen on raw sea water used for cooling, yet my Petter and others went for years with sea water.  There does not appear to be an easy solution to this with the new Yanmar when it comes to fresh water cooling as a heater needs to be built and a KEEL cooler is likly a solution.  This is what I am told.

Can you please comment on your repower experience as to what you used for a water circulating system using fresh water or if you went sea water cooled?
Bottom line I am wondering why I would not go sea water cooled.... The engine is new and the mainance will be flawless.
The other bottom line is expense - yes I am aware you buy a new engine and you want the best possible solution you can afford with the engine operating well and long.

Any commnets please.

  • From: Montreal
  • Registered: 2005-04-22
  • Posts: 259

Re: New Engine NEED ADVICE please

Let me see if I get this straight:  you have a new Yanmar to be installed on your boat.  The Yanmar is cooled using freshwater.  The choice is whether to fit a heat exchanger so that sea water can be used to cool the fresh water and thereby the engine, or to fit a keel cooler so that the cooling takes place outside the hull.  A keel cooler might eliminate a circulating pump *IF* raw water is not used to cool the exhaust.  Otherwise you are still pumping raw water from a through-hull into the boat.  The little bit that I know about keel coolers suggests that they shine where the exhaust is a dry-type, and where water is very muddy such that filters and pumps are prone to clogging. 

Insofar as plumbing raw water directly through the engine, I would not recommend it.  As a Petter owner, corrosion of the aluminum block is a fear for me -- so many dissimilar metals -- iron pistons, steel bearings, aluminum block, bronze pump, etc.  To my mind installing a new engine is a chance to do this right.  Definitely no salt water inside the engine.  Salt water should stop at the heat exchanger and then pass directly to the exhaust for overboard discharge. 

(Aside:  the corrosion question has me so paranoid that I have bought a small water tank for plumbing into the engine cooling system.  Using this tank I can flush the Petter's cooling lines with a burst of fresh water before shutting down the engine.)

Also, your new engine should come with the heat exchanger already in place for installation.  Is the heat exchanger not included in the purchase price of the marinized Yanmar?  I don't know about the keel cooler.

Anyone else read Paul's question differently than I have?

Good luck with the engine!  It is a fun project.

  • From: Petit Rocher NB Canada
  • Registered: 2009-12-15
  • Posts: 55

Re: New Engine NEED ADVICE please

Hey Paul,
I fully agree with Christopher. The vast majority of sailboats have their system cooled with raw water. It is taken for granted that the motor itself is kept cool by a closed circuit of an antifreeze solution which is cooled by circulating raw water drawn in by the impeller at the rear of the motor. Good idea to install a filter in the intake hose even if you have a strainer on the hull. A keel cooled system drawing no water from outside would be advisable in shallow murky water such as the barges in the inner canals in France but not recessary in open water. Perhaps it would be a good idea to check with other marine mechanics or with the guys at Binnacle to get a second opinion.
Good luck with your project.

...)))) May the wind fill your sails and the sun shine in your face cool
  • From: Ottawa, On
  • Registered: 2005-03-10
  • Posts: 353

Re: New Engine NEED ADVICE please

Aside from going with a bigger engine already quipped with a heat exhanger theres really not a whole lot of options.  To fit a closed cooling system to a 1GM10 is not impossible but would require a fair amount of custom fabrication including the addition of an engine driven raw water pump, adaptation of a heat exchanger to the existing cooling water system, addition of a pressure tank as well as rerouting some exhaust water lines.

In short, I would not worry too much about using a raw water cooled engine in salt water  The 1gm10 in my Contessa saw 2.5 years of salt water cruising.  Exhaust elbow and head were fine, zinc was changed regularly.  Minimal calcification in water passages in the head. 

Just flush with fresh water for extended storage or sailing passage times, keep on top of the zinc and exhaust elbow! and she'll provide years of reliable service

stefan_d's Website

  • Adrian
  • Adrian
  • Administrator
  • Offline
  • From: Toronto, Ontario, Canada
  • Registered: 2005-04-18
  • Posts: 542

Re: New Engine NEED ADVICE please

I agree. It may be the case that a heat exchanger might increase the life of the engine, but we're routinely seeing engines 20 or 30 years old that have been raw-water cooled their entire lives still chugging along.

Adrian's Website

  • From: Montreal
  • Registered: 2005-04-22
  • Posts: 259

Re: New Engine NEED ADVICE please

Speaking of zincs -- my old Petter lives in fresh water and I do not know where the zincs are (or were) for the engine.  Can anyone give me a map or a photo or something so I can get this addressed?

Thanks!

  • From: Victoria
  • Registered: 2006-04-30
  • Posts: 8

Re: New Engine NEED ADVICE please

We have a Yanmar 2GM 13 HP, raw water cooling, with 6-7000 hours on it and was still cooling just fine. We had it rebuilt last year and if it can hold another 6-7000 hours we will be very happy. We never had problems with the raw water cooling as long as you ensure that the intake valve isn't plugged with seaweed, etc.

  • From: Belle River, Ontario
  • Registered: 2005-03-20
  • Posts: 143

Re: New Engine NEED ADVICE please

Hi

Was just at the Chicago boat show and the Yanmar rep tells me that the 1GM10 is not available anymore... don't meet emissions or something.... got to go with the 2GM13 HP.

  • Adrian
  • Adrian
  • Administrator
  • Offline
  • From: Toronto, Ontario, Canada
  • Registered: 2005-04-18
  • Posts: 542

Re: New Engine NEED ADVICE please

I bet the 2GM13 is a fantastic engine for the Contessa. Much smoother than the 1GM10, I figure.

Adrian's Website

  • From: Nova Scotia
  • Registered: 2010-07-28
  • Posts: 19

Re: New Engine NEED ADVICE please

The 1GM10 has been discontinued; the last engine coming off the line was summer 2010 I have been told.  The Emision issues was an American decesion so they cannot be sold in the States.  The 1GM10 can still be purchased in Canada if they are to be found.  They are and were pretty popular and also a good, but snug fit for the Contessa.  I have no idea how tight the new Twin will be, but I am going to assume it is a bit larger?
Still the old Petter and its issues; that the new engine will replace should be a great engine and a better summer ahead.

  • From: Victoria
  • Registered: 2006-04-30
  • Posts: 8

Re: New Engine NEED ADVICE please

Yanmar have change from 2gm13 or 2gm20 to 2ym15 with small change to where the water pump is, still a nice looking motor.

  • Registered: 2006-09-20
  • Posts: 175

Re: New Engine NEED ADVICE please

The corrosion related failure point on raw water cooled 1GM10's is the steel oil line that runs across the engine just below where the water pump mounts.  Any drips from the pump shaft seal - and its very common to get grooving of the $%^*ing expensive shaft if you are in estuary water with any significant amount of suspended silt - land right on this steel line.  Have a replacement line made up in copper and you can be pretty confident your engine wont dump all its oil in your bilge and promptly seize.   

If in silty water, it is worth cutting a drip deflector from a sheet of fairly thin polythene and fitting it between the water pump mounting flange and the block.  Replace all the pump mounting bolts with A4 or 316 stainless and put Duralac bichromate paste on all the threads and you will have no further trouble so long as you keep the pump's shaft drain holes reasonably clean.  Otherwise the buildup of salt from a slow weep can eat away your aluminum timing case cover where the boss for the bottom pump bolt is. 

The injection elbow is a wear part and should be checked with a bright torch and a mirror to look up it annually as a minimum.  Also, to avoid corrosion it is best to remove both the exhaust and water hoses and seal it with a plastic bag and tape, preferably with a desiccant sachet for your winter layup.   You should bag the intake as well, but thats' far less critical.

Failure to check the elbow results in undetected pinholing which results in exhaust manifold and exhaust valve corrosion. If it goes undetected for long, you will then need a new head at over £500 + misc parts and labour.

It is also a very good idea to leave the engine close to TDC on the compression stroke (when you hear the injector creak its right where you want it) so both valves are closed and you don't get rusting in the cylinder or on the valve seats due to condensation from the damp atmosphere produced by the waterlock muffler and the salts in the hoze if you aren't going to use the engine for the next month. Its dead easy to do, just decompess and crank very slowly, stopping when you hear the injector. 

My 1GM10 is 25 years young and still going strong.