212 engine performance
I have had my Mariah since November @ 76 hours. I am currently at 98 to date. Runs good, smooth new stereo is awesome. My question is perfomance. I dont think my engine is performing like it should @ est. 250 hp. I had an older boat that had a 4 barrel quadraunk on it that screamed. I do have a new 21 pitch Mercury Mirage just added this weekend. It had the old 21 pitch alluminum that I keep for backup. Trimmed up with 600 lbs of people in it only turns a little over 3900 Rpm @ 42mph. That is plenty of speed, but I would just think it could handle a little more. I guess I need to do a complete tune up and put a new fuel filter on it(possible restriction). The boat DOES NOT hesitate, thats why I havnt done all this yet. Any ideas?
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Yes, it sounds like your boat needs a tune up. Normal WOT rpm's are 4200-4800
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Yes, something is certainly off. My 202 with nearly the same power package (I have a carbed 4bbl) will do 50 mph with 4 persons and a full load of fuel.
I don't think your prop is the issue. I've run both aluminum and a stainless merc vengence of the same pitch (21p) and the performance is approximately the same: 4600 to 4700 rpm@WOT. |
my 212 runs at 4700 rpms at wot and does 60mph with 4 people in the boat. I have a 23p 5blade stainless prop called the high five.
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darrel,
I looked at the high 5. I found this one locally on craigslist for $250 and it doenst have any marks or scuffs on it, practically brand new. I priced it new and it was nearly $500 for the prop and hub. I wanted to get more pitch but if im only turning 4000 rpm then a more pitched prop will make it turn under that. If the funds allow this week im going to put a set of plugs, cap, rotor, and wires and do a service on the engine. Maybe for some reason im not getting all the through out of the throttle. I will look over this week. |
also, keep in mind, mine is NOT a 350 mag. Its only rated @ 250hp.
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I don't want to sound like a broken record, but I had this exact same symptom last year. Mine also had a little knocking/growling noise that I wouldn't have known was wrong since the boat was new to me. Turned out to be the gimbal bearing. Does your's have any sort of rattling noise while at idle?
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no, but if you rev the engine more than an idle it does seem to make a little noise. The previous owner had the drive takin off, and everything changed. However, I dont know what "everything" is.... Is there any other ways to check the gimble bearing. SOB im gonna be mad if I have to pull that heavy thing. How hard is that to change? I do have a foklift so it wont be that big of a deal. I will definetly run her on the hose tomarrow and listen CLOSE. It seems that when im turning at an idle there is a definet noise.
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well after reading this http://www.sterndrives.com/precisionparts/421.html I have figured that the gimble bearing is the suspect. NO MORE BOATING for me for a while. Typically how difficult is this task? Can it be performed on a saturday. or is it a TOTAL weekend Task. Im am very mechanically inclined and not worried about doing this, but just tryin to get a time frame. What is the best place to get murcruiser parts online?:shakehead::punch_out:
Now I feel like vomiting! |
If you work hard you should be able to get it done in a weekend. I did my gimbal bearing, u-joints, gear end yoke, and shift cable over the span of two weekends. You will need a slide hammer to pull the old bearing out and tool (you can use a wood block and go slow) to knock the new bearing in. You will also need an alignment tool. The first tool I would get is a Mercruiser service manual for your engine and drive!
If its been more than 3 years since the bellows have been changed I would go ahead and replace them as well. ~J |
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