Merc 502's? Racing engines or good for cruising?

[POINTER94]

I am looking at a cruiser with twin 502's. Most racing engines I know typically require frequent tuning to keep them running right. Not necessarily a maintainance nightmare but let's say more intensive. I believe the 502 is a racing engine. I may be wrong. How does it compare to the 454? Fuel consumption? These are carb'ed 1994's. Any history with these beasts? The are in a 35 ft cruiser....

Enery once a nd a while there are some models to look out for. (470's) and I know nothing about this engine... There doesnt seem to be much out there on these that I can find

Oh yea they are hooked to bravo outdrives...

 

[Don S]

Re: Merc 502's? Racing engines or good for cruising?

They aren't racing engines, that is the standard big block engine used by Mercruser.
There are racing versions of that engine, but not what you typically find in a 35' cruiser.

Enery once a nd a while there are some models to look out for. (470's) and I know nothing about this engine... There doesnt seem to be much out there on these that I can find

You must not be looking in the right places http://forums.iboats.com/showthread.php?t=566372

 

[QC]

Re: Merc 502's? Racing engines or good for cruising?

Love the 470 screen shot, Don!! Saving that for future "tell me about the 470" threads. I think Pointer was saying there's not much about the 502's . . .

Good engine. Bravos good. Post up more on the boat itself in the Boat section?

 

[POINTER94]

Re: Merc 502's? Racing engines or good for cruising?

Sorry Don, Poor wording on my part. I know very well about the 470 what I don't know about is the 502. I am hoping the 502 doesn't have the same kind of history as the 470... If it does I can scratch that boat off my list of potential purchase list. I searched several variations of 502 and merc and got just a couple of threads...

 

[haulnazz15]

Re: Merc 502's? Racing engines or good for cruising?

Nothing wrong with the 502's, they'll just eat more fuel than the 454's purely due to cubic inches. No shortage of power on tap though!

 

[Don S]

Re: Merc 502's? Racing engines or good for cruising?

Merc used 8.2 (502) all through the 90's as inboards and IO's, then went to the 8.1 (496) in 2000 for a while.
No real problems with them, other than they are thirsty for gasoline.

 

[sschefer]

Re: Merc 502's? Racing engines or good for cruising?

I've run the 502 in my former North River. Ran it in front of a Hamilton Jet Pump (turbine). It was an excellent motor with no problems what so ever. The 502 is a torque monster (my personal feeling) and in my case where I ran in shallow muddy water and on rivers it was the motor that always had the juice to blow mud when the others couldn't. It cruised effortlessly at 40mph and had no problem pushing the boat to 55mph if I wanted it (rare).

The only thing I ever heard was that they tend to breath heavy and because of that they have been said to have had internal corrosion problems. I never had it within 20 miles of Saltwater but I can tell you they do breath heavy but it's not a problem as long as you cool them down with the hatch cover closed which most people do anyway. I never experienced the problem myself but when I sold it, one of the buyers questions was if I knew about the problem or not. Odds are he just got the info from heresay because I've never seen it documented anywhere.

 

[POINTER94]

Re: Merc 502's? Racing engines or good for cruising?

SS, I would be running on lake Michigan so salt wouldn't apply. I don't need to have that much speed but you can plan for gas you can't always plan for breakdown or service. FYI, I had the pleasure of meeting the designer of the Berkeley jet drive, Eugene stadelhoffer. Talk about a neat guy. Saw pics of boats with what essentially was an irrigation pump strapped on. He did a lot of work in the San Joaquin valley with engine driven pumps because there was no electricity out in the fields. And you are right with those jet drives it was all about torque.

 

[sschefer]

Re: Merc 502's? Racing engines or good for cruising?

I would have to say that the 502 is very reliable but as you seem to understand, fuel consumption isn't wonderful so they are expensive to run from that aspect. Funny you should mention Eugene, I've never met him but ran accros a few articles about him. The company I work for owns the property and buildings that were the former Jacuzzi pump factory in Richmond, Ca. Our winter corporate offices are there also.

 

[POINTER94]

Re: Merc 502's? Racing engines or good for cruising?

I worked for 15 years for Berkeley pumps and he was the founder. Last I knew his son took over the place after they sold out to delaval. Now is owned by pent air. The factory is in Berkeley CA and my last contact had them doing business as ARMS. All Repair Machine Services. In the same factory in Berkeley. If I had an old Berkeley jet drive, I would go there for any advice assuming they are still open. He had designed a submersible pump for handling baby carrots that he was doing well with last I spoke to him...

 

[RogersJetboat454]

Re: Merc 502's? Racing engines or good for cruising?

SS, I would be running on lake Michigan so salt wouldn't apply. I don't need to have that much speed but you can plan for gas you can't always plan for breakdown or service. FYI, I had the pleasure of meeting the designer of the Berkeley jet drive, Eugene stadelhoffer. Talk about a neat guy. Saw pics of boats with what essentially was an irrigation pump strapped on. He did a lot of work in the San Joaquin valley with engine driven pumps because there was no electricity out in the fields. And you are right with those jet drives it was all about torque.

The 470 was Mercury's attempt at building there own engine.
The 502 is a big block Chevy, built by GM, and marinized by Mercury. GM had been building these style big blocks for 29 years by 1994, so everything had been figured out. The 502 is no better or worse when it comes to reliability compared to the 454. Just more displacement, and more thirst.