Engines and drives removed any tips.

[Golfgippsland]

Hi I have removed both transom assemblies from my boat due to excessive corrosion. So obviously the engines (mercruiser 470's four barrel 180 hp) are sitting in the work shop. I have just received the new transom assembly's , new exhaust's and they are being installed now. I am changing the oil, plugs, points and checking the heat exchangers while the donks are out is there anything else I should be doing before putting them back into the boat. Thanks in advance. Cheers from oz.

[Viper]

I assume you've checked the transom prior to reinstalling the transom assemblies? If there are any questionable areas around the assemblies (wet), now's the time to address them.

Did the new assemblies come complete with new bellows, gimbal bearings, senders, lower shift cable, etc.? Now's the time to replace them.

If I recall, the starters on the 470s aren't easy to get at in some brands. If yours are difficult, you may want to be proactive and send them out to be freshened up prior to reinstalling the engines.

Check hoses, belts, etc., and look for signs of any leaks (fuel, oil, coolant, etc) that would be much easier to address before reinstalling. Look at the entire raw water circuit and assess the components if they're more than 5 years old such as the exhaust elbow.

Now's the easiest time to replace all the coolant and start fresh.

Have your 470s been upgraded with alternators?

[SplashyLady]

Check the instrument connections carefully and make sure the tach is accurate. The 4 cylinder 470 engines were once rated for 4800 RPM wide open throttle, but Mercury later reduced that to about 4200. These engines do not like high RPMs! I've seem some cracked pistons and other serious damage from running a 470 at high RPM. So if you were running around 4000-4200 before, you are probably fine, if you were running 4800 or so, I would consider a re-prop to get the RPMs down.

Good on ya, Mate!

[km1125]

I'd be looking at all the gaskets and seals and if there is ANY sign of weakness, I'd replace them. Obviously much easier to do when out of the boat. I have a rear crank seal the drips just a tad but not worth pulling the engine to resolve!!

[tomschauer]

I assume the 3.7 liter motor ran fine when removed? These are pretty good motors, but are now very expensive to repair. And its increasingly difficult to find remanufactured motors or even a good block to start with. If there is any issue with them, I would consider changing to 4.3 liter motors while everything is out of the boat. It will cost some $$, but the 4.3's are pretty durable, almost bullet proof, and parts are everywhere and very inexpensive. They will fit nicely in your santego and you can use the same out drives, even add a bit of prop pitch if you want.

[Golfgippsland]

Thanks for all the responses, yes the mercruiser's are in great condition no leaks of any sort. Could eat your breakfast off them. The transom is as solid as the day it was built. Replaced all fluids. Yes the two transom assemblies have been totally rebuilt using new parts. Cables ,bellows, steering and new exhaust's and new custom made elbows. Don't have any problems with the starters so will leave well enough alone. I didn't think that 4.3's could fit without major changes. I thought the transom assemblies were closer together on the 3.7's also different engine mounting?? Thanks for the electrical tip checking all connections today.

[tomschauer]

The 4.3's will fit no major changes, you just need the new motor mounts, they will sit on the stringers just right. Leaks were not a big problem on the 3.7''s. it was main bearings in the aluminum block. So, it doesn't matter what they look like, how do they sound? If they had any knocking, they are near the end.

[Golfgippsland]

Thanks for the information I will keep it in mind about the 4.3's for the future. My 3.7lx's are in great condition so they will be staying put for the moment. I know a lot of people don't like these engines at all but I love them super economical for me as they spend most of their time under 2000 rpm. Don't get me wrong they can be thirsty if you open up those quadrajets. I have read enough about the mercruiser 470's to know that they don't have many fans but I am one of them. I love the look on people's faces when they work out that 3.7 litres is huge for a four cylinder donk.

[tomschauer]

Yes they are a big 4. The head is actually from a 460 ford motor.

[Golfgippsland]

Yes I've been thinking I might pick up a couple of cheep used engines to rebuild using aluminium heads. I know I can build a great top end for these engines just need to investigate strengthening the bottom end. Some people have had success doing this using the 470 in hill climbing cars due to the massive amount of torque they can produce. A project for future winter months maybe.