HEY CTT..and the rest of you I/O guys
 

OK,

I got the 470 Mercruiser, and she is original so she is 23 years old. Now I dont like to push her, so I run her around 3500 or 3700 RPM max.

What are you guys running this motor at? Harder? Any idea what top speed is at 3700 RPM?

thanks ;D

Re: HEY CTT..and the rest of you I/O guys
 

Hey CY, Ive got the same motor. I just rebuilt mine myself,and still breaking it in. Ive run it to 3500 rpms but only for a few minutes. Im not sure how accurate my factory tach is. It seems to run really smooth with no strain about 2800-3000. Im not sure about the speed, cant get my Hummingbird to tell me how fast Im going. Are you still running points or have you converted to electronic ignition. I installed a pertronics ignition,runs good but dont want to fire up when its hot.

Re: HEY CTT..and the rest of you I/O guys
 

cfelton, check voltage at the coil when hot, odds are the resistor wire is breaking down, back track(take the tape off teh harness and unwrap it) the purple wire back up the harness till you find a short piece of hard wire thats shrink wraped, cut the wire just past this so it eliminates the hard wire and replace with a new purple wire going to the coil, if that doesn't fix the problem, make sure your shift switch isn't sticking.
As far as the rpm's on a 3.7, we used to spin them 4600-4800 wot, cuise around 3400. Biggest problem you'l find if you twist them harder is they break rockers

Re: HEY CTT..and the rest of you I/O guys
 

Mines an 898, so I can't help you with yours. I like cruising at about 3500 rpm's though, wide open is 4100 without messing with the trim.

Re: HEY CTT..and the rest of you I/O guys
 

thanks boys, and yes I am running points, I have taken a lot of crap from a lot of people here about switching to electric ignition but I feel "if it aint broke dont fix it" I did have to replace the coil last week and I could NOT find the resistor. Anyone know where that thing is?

thanks for the input boys...... ;D

I always run mine around 3500 and 3900 max.. ;)

Us I/O boys got to stick together around here, we are few and far between. :'(

Re: HEY CTT..and the rest of you I/O guys
 

That is when mine starts the easiest. When she is warm. ;)

Re: HEY CTT..and the rest of you I/O guys
 

I have the 898 also. Top out around 3950.
I cruise 2500 choppy - 3000 smooth.

Re: HEY CTT..and the rest of you I/O guys
 

any idea what the speeds are at those RPMs ???

Re: HEY CTT..and the rest of you I/O guys
 

2500 puts her about 21-22 mph I'm topping out around 39 at wot now. I just haven't been able to really play with the high end much do to the chop and don't see any reason for me to be going anywhere over 30 mph, except for the occasional rush factor. 8)

Re: HEY CTT..and the rest of you I/O guys
 

sorry cy.
i have the 350/260.
runnin her about 2600 rpm.
guessin at about 22-27 mph.
dont really know.