Re: Mercruiser 470 Magnetos
Jilly...much has been discussed about these engines on this forum, search for "470", "3.7" or "3.7L". Here are a few sites to look at regarding the charging system and cam shaft driven water pump and cooling system and short answers to your questions.<br /><br />A. Charging System - designed with stator (magneto) and water cooled volt regulator, a poor system, easily converted.<br />B. Cam driven water pump - prone to bearing wear, once again, poor design requiring extraction of cam shaft to replace seals, probably a once in 6-8 year maintenance requirement, belt driven pump would have been far better.<br />C. All had closed cooling systems, early ones had 3" heat exchanger which was inadequate, replacement with the 4" model works well, but as with closed cooling systems that depend on the lower unit impeller for circulation, you'll need to properly maintain the rubber impeller. Ireplace every other year.<br /><br />This is good, talks about twin engine charging conversion with 3.7L:<br />
http://www.jimthompson.net/boating/Electronics/Voltage_regulator.htm <br /><br />Cam driven water pump issue and fix:<br />
http://www.sterndrives.com/470information/470coolantleakrepair.html <br /><br />Overall, the 470/3.7L is a torque monster and a mechanically reliable engine. Considering the cost to repower if you already own one (or two), it's well worth modifying to make the poorly designed systems better, particularly the charging and cooling systems. You can get great value if you knowingly are buying these, they run forever if you solve the cooling and charging issues. I've dealt with the cooling and charging for about $700, and only regret not converting the charging years ago.<br /><br />Answers to Q's<br /> <br />1. No, Yes, and do both engines. See other posts by doing search for places to buy conversion kits ($350 to $500 per engine). ( bought from eBasicpower and Breezeworks)<br />2. As with any regular (alternator)charging system thye serve double duty, but on a secondary basis by charging the battery. Not like the old motorcycle magnetos that often didn't have batteries.<br />3. Definitely, should have done mine years ago.<br />4. It is recommended that the stator and magnets inside harmonic balacer are removed, I did not remove in my conversion because of skepticism, only my regulator was bad. The only problem could be magnets detaching from inside the harmonic balancer falling off and affecting balance (but it does save a lot of time leaving the stator and magnet, avoiding remaoval of the balancer).<br />5. Yes, but sorry, don't know what FWC is<br />6. Do not know<br />7. Range of HP 165 to 190 depending on carburation.<br /><br />Helpful for schematics and replacement parts:<br />
http://www.mercruiserparts.com/mercruiser_parts.asp
