Blown Merc?

lahiggs · Jul 20, 2004

I have a Citation w/ 4.3L Merc Alpha 1. Yesterday while I was out in the water I noticed that at an idle, the temp was around 180, when I would take off down the river it would drop to 135 or so. I had a feeling the impeller was about to go. It did and the motor died while the temp gauge was around 210 or so. I had it towed in from there back to my trailer. The motor was smoking a bit and didnt smell too healthy. Is there a chance that I have junked my motor?

BMDODGE · Jul 20, 2004

Re: Blown Merc?

how long was it at 210 ??? does your gauge go higher than 210 ??? 210 isn't really high and if it wasn't run too long at that temp - you "might" be o.k. - did you shut her down when you noticed the temp ?? or did it die..? Bruce

csanna · Jul 20, 2004

Re: Blown Merc?

I did kind off the same thing with a 3.o 4 cyl I replaced all the gaskets and put in a new impeller. And she runs great. Actually the new impeller coolled so well I didnt even notice my engine water pump belt came off, the impeller was doing all the work. It is very hard to crack a block from overheating. Now freezing water in your block is a whole diff ball game!

lahiggs · Jul 20, 2004

Re: Blown Merc?

my guage goes to just a hair over 240. it has a blue section, a white section and a red section. it was just borderline between white and red. i shut it off. the motor still cranks so I know that its not locked up. It is in the process of getting a new impeller right now. i dropped it off at the dealers this morning. just want to know what im looking at cost wise here.. thanks for the help.

lahiggs · Jul 20, 2004

Re: Blown Merc?

Does anyone know of any mods that I can do to a '87 4.3L Alapha 1? I would like to get a little more power out of it if its not junk. I am going to change the prop from a 19 pitch to a 21 to gain a little more top end. The hole shot now is great and I dont think going to a 21 would affect the bottom end torque too much? Any suggestions/thoughts?

Chris1956 · Jul 20, 2004

Re: Blown Merc?

WVboater, My '88 4.3LX has a 4 bbl Rochester carb. The motor is rated at 205HP. You might ask this forum if this is the only difference?

lahiggs · Jul 20, 2004

Re: Blown Merc?

Mine only has 175HP. It does only have a 2bbl carb though. Would it be very hard to change to a 4bbl carb? All I would need would be a new carb and intake...right? I dont think that would add 30hp though.

Bondo · Jul 20, 2004

Re: Blown Merc?

It'll make a Big Difference........... Starting from Your point, It's the Biggest Bang, For your Buck$.....

steve n carol · Jul 20, 2004

Re: Blown Merc?

wv and others, read a story in a san diego forum bout a guy who was 12 miles offshore when his impeller tookadump. He dumped his live bait and utilized the bait tank pump to get him back in.

achris · Jul 20, 2004

Re: Blown Merc?

Only difference between the 175 and the 205 is the intake manifold and carb. Everything else is the same, cam, crank, pistons, distributor and timing curves, heads, exhaust manifolds. Chris............

lahiggs · Jul 21, 2004

Re: Blown Merc?

where is the best place to get a deal on a carb and intake?

lahiggs · Jul 21, 2004

Re: Blown Merc?

I read on another topic about oil pressure reading about 75. On mine I am reading about 50. Is this ok?

Skipster1 · Jul 21, 2004

Re: Blown Merc?

If you are going to be that detail-oriented (a good thing, especially for a boater) you should go ahead and buy a manual. Oil pressure usually - USUALLY - ranges from 30psi (idle) to about 50-60psi WOT. Yours appears okay but, here again, the manual would ease your mind. I'm no expert on oil systems but 75psi sounds abnormally high???

henrymbrito · Jul 21, 2004

Re: Blown Merc?

Similar thing happened to my Merc 3.0. Temp went up to 210 or so, lots of smoke and rubber-like smell. I shut-off motor to let cool, and I was able to get it to crank, but would not start. Took to shop, replaced water-pump kit (inpeller included), exhaust flapper and some other plastic part which I can't remember. Damage was $425.00 which I was in a sesnse glad to pay since I was thinking it would be much worse.

lahiggs · Jul 21, 2004

Re: Blown Merc?

Thats exactly what happened. Lots of smoke and burnt rubber smell, like a belt melting or something. I just left the shop and the impeller is on and the motor is running, but the starter is going out so it will be another day before I can get in the water. I can't wait to get it back, I am on vacation and no boat to use..its not fun...! Thanks for all the help so far, I really appreciate it.

mercrewser · Jul 21, 2004

Re: Blown Merc?

You may want to check exhaust flappers in the exhaust section. They are probably shot from the overheat. 210 degrees is not that hot as engine goes. But the stuff in your exhaust system is not ready for uncooled exhuast gasses

achris · Jul 21, 2004

Re: Blown Merc?

Good place to start for manifold and carb is the Holley website. www.holley.com Chris........

bluewater19 · Jul 21, 2004

Re: Blown Merc?

Your 175 hp 4.3 is really only 155hp at the prop. I have the same engine and did the swap to the 4bbl. now I have 175 at the prop.I suggest making the swap,you will love it, I did. Look on ebay for the carb and intake I paid around 200 for both. I have a very heavy 19.5' cuddy cab that would do 38-40mph(gps) at wot with a 21 pitch mirage plus. After switching to the 4bbl intake and manifold my top speed with the same prop is now a solid 44mph(gps). I have the holley 600cfm that is spec'd for the volvo 4.3 And I think that with a little bit lighter spring the vacum secondarys would open more and give me even more power. I have opened them manually at WOT and that baby takes off even faster. Good luck!!

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