Offshoreonly.com - Kindly forgive my ignorant first post here

Quote:

Originally Posted by brew80

I'm new to this site and to the boating world. Just purchased a slightly tweaked 1988 Baja Force 235 7.4L Mercruiser Bravo 1 drive. Had the compression checked on it and had only a 3 lb difference between lowest highest cylinder. 125/128

Question is this compression too low and should i be concerned with this compression ratio per cylinder. I was told that i should be in the 140 to 150's range. Does it sound as thought the previous owner didn't take care of the motor or does this sound about normal range for this motor.

Also where should i be running this motor at rpm range to be safe. Wide open i'm around 5k. This is a 454 big block 4bbl with an after market cam and rollers. No idea on the specs.

One last note to end... i was idling along this last weekend and hit a shallow spot and got caught up in some muck. I reversed and was able to break free.. no chips or dings in my prop and motor didn't overheat.... ran fine for the rest of the day... Should i be concerned that i sucked up a bunch of muck up through my drive ?? I did run it the rest of the day and didn't notice any difference in performance. Thanks for any and all input to this amateur wanna be boater.

You still have good compression and all cyl. are equal which is good. How many hrs on motor? I wouldn't worry about it.
You may post in Tech section they are smart.

You can run wide open at 5000. I would not run longer than 15-20 min at a time, which should prove your point.
Then back down to 45-4600 for as long as you desire.

Good you hit muck and not rocks. You will be fine if you ran all day with no overheating which you want to watch like you did.

This is a great site and you will learn alot. Sometimes it takes a few days to get some posts. Remember to wear the PFD when hammering the rig. :evilb: