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3.7 litre 4cyl 470

A

aven2rus

New member
I just purchased a 1989 Sportfire with the 3.7 litre 4cyl Mercruiser 470 and have a few questions.

1) What should I do as far as preventive maintenance?

2) Any known problems I can be proactive with? Did search and found alternator upgrade info.

3) What if any performance upgrades?

Thanks in advance for your input.
 
I have a 470 also. It is a good motor in that it is light (aluminum block) powerful for its size, and fuel efficient. An all around efficient motor, even if it is not the most powerful one available.
THe trouble prone areas are the alternator...if your charging system dies, just convert. They sell the kits for $400 or so, but if you are mechanically inclined and have some spare alternator brackets from the junk yard, and a way to cut them (cut off wheel), drill, etc., you can make your own bracket for next to nothing and buy a $99 dollar one-wire GM style alternator (marine version, of course.)
The other problem they have is that they can run hot...and they don't like to run hot because of the aluminum block and cast iron head...they blow head gaskets. Just keep up on your cooling componants.

As for performance, there are 4bbl manifolds available, and apparently they can use the extra breathing capacity.
Also, I swithed out my points for pertronix ignition.
They are made from half of a big-block Ford, so I guess you could use performance heads and valve-trains that are readily available. I don't know how much they will help.
 
let that 470 just run.. its realiable, and effiecient.. i would't advise trying to hot rod it.. yes it blows head gaskets, and they can be a lil pain to change, you must run 40 wt oil in them or you'll have more problems than you can throw a stick at.. other than that enjoy the efficient cruising.. they are good lil engines..
 
Thanks for the advice.

In the othe rforum I was told a 21 pitch prop performs nicely. I checked today and it is a 23.

It also has a hyrofoil on it if that makes a differance.

I won't be able to get it on the water until I'm done traveling for work in 2 weeks so any suggestions that will make that first trip smooth are greatly apreciated.

This is my second boat, first I bought only last August and first IO so I am newbie for sure.
 
I have a 23p and it turns 4400 rpm with just me in it. It turns 4100 with 3 rather large people on board (2-230 pounders and 1-170 pounder) plus stuff.
So a 21p would be a good alternative if you are going to haul more people around.

BTW, my boat is a 19' Eluder
 
couple of questions on the 3.7L----the one in my 85 diplomat runs very well but i notice a few things---1)the antifreeze although nice and clean and was topped right up in the tank where the radiator cap goes when i got the boat at the beginning of the summer----now seems to be pushing it out into the small plastic reservoir at the bottom of the engine compartment and then not recovering it by itself. could this be just a simple bad radiator cap?? 2)as far as oil and an oil filter goes----it was all clean and had been serviced when i bought it but after some long weekends and lots of getting out i want to change it---the previous owner gave me the suction tube kit to change the oil through the dipstick tube but what to run after??? straight 40 weight??---the clymer's manual i have for mercruisers says not to use any car grade oils (10w30---10w40---etc.) ive noticed when checking fluids before every time out that i use a little oil----im not overly concerned as ive heard this is normal and this engine does have years and hours on it. ive topped it up with some 20w50 on a friends recommendation but figured i'd ask here for the oil change. also, it has a napa oil filter on it---replace with same?? read in the manual something about marine filters being a little different than regular auto oil filters----true or false??---thanks for any advice and sorry for the long post....

steve
 
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there is a service bulliten on that engine that is as old as it is.. you should run straight 40 wt oil.. you'll run into problems at lesser wt oils.. that engine builds alot of oil temp, for as small as it is
 
thanks for the info on the site butch----i went to check it out but my crappy computers been on the fritz again---good thing AOL never got into building boat engines or we would all be stuck at the dock most of the time----
 
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