leaky

Hi,

I'm finishing a new straight inboard boat, it's not a race boat, it's a fishing boat, and it's on the line where they do well with gas or diesel engines. Lately most of these hulls get diesels but the builder actually advocates gas engines for the weight and cost effectiveness - I like gas engines and that idea, it also helps make weight & noise issues easier to overcome and I can then have an outboard as a backup engine running off the main fuel supply.

I had spec'd the whole project out for merc 8.2 430 HO, which is a great HP range for what I'm doing. I wanted the electric controls since it makes multiple stations a lot neater and cleaner, have been tired of fighting with cable adjustments and creep for years. Was looking forward to throttle changes with one finger, electric shifting, etc.. etc.. After doing a bunch of research I couldn't find anything bad about the merc setup and was sold on it.

Now when I went to get a quote from a friend who services merc primarily, he is completely poo-pooing the whole setup. He says the cats are extremely problem prone, the engines require constant baby sitting w/ a computer, doesn't like the electric throttle and shift and says it's temperamental. He is basically advocating using some older MPI technology, which I believe is a fairly grey (or dark) area legally in a brand new hull, but maybe it's not - I thought the EPA regs applied to the hull but maybe it's a just a matter of what engines they can produce and you can use whatever you can get your hands on, not sure.

Looking around I still can't find much going wrong with merc cat-equipped inboards lately, but maybe merc is just doing a good job hiding it.. Same for the electric controls, I don't see many complaints. Does anyone have an opinion on the setup and have good or bad experiences to share?

As far as the cat's go - it looks like you can delete them fairly easily with a couple different methods, either via a cat delete sensor or a whole aftermarket computer - is that correct? Does it mess with any of the existing merc electric controls stuff when you do that or does everything else work the same, just without the cat?

Thanks in advance,

Jon

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iTrader: (9)

This engine for the first few years had many Service bulletins for fixing problems and updates. There was a few software updates as well. There is not that many out in the market place especially if you did an apples to oranges comparisons since its been out 7 years now as the 496 from 2001 thru 2008 for 7 years was about 400 to 1 in sales. But many factors play into as well. Many selling in the markets are outboard engines not I/O's.

The cat systems have more than zero problems. Actually Volvo Penta has the least amount of Catalyst system issues.

Anyways this engine would not be my first choice - hard to work on - more complicated systems in the mix here plus not many seen them out in the market place to even work on them compared to other engine models currently. I would prob take an LS CAT engine over the 8.2.

leaky

Which model would you be looking at?

What he was voicing were concerns over the cat's getting wet and failing, normally I wouldn't question the guy except when I asked he said he hadn't actually seen one failed yet, but like you said - not an extremely popular engine either.

What sort of thing makes the 8.2 more complicated than something else that's current? Sounds like maybe I had it backwards but I always figured with everything being computer controlled, cat's, and multiple o2 sensors now, the simplest thing is going to be a simple big V8 versus variable valve timing or direct injection in a smaller block.

In the beginning when I was spec'ing out the project I considered Volvo, however they are doing something so they state (forget if it was the larger engines or all of them) the gas models no longer support straight inboard setup; like they did something such that you couldn't bolt a regular gear on them without an outdrive. Secondly seemed more of a liability, since I know I can find a mercruiser part at least at a discount if not cheap, volvo maybe not.

Also considered the smaller blocks and it's kinda tempting to shave 200+ lbs, like maybe a towsport engine might be the way to go (meant for straight inboard).. Not to mention way cheaper, like maybe 8K less.. What I questioned there is when a 502 makes 150 HP before it even hits 2000 RPM, seems like a real good thing for trying to get a nice low RPM cruise, and what I know about turned up smaller displacement engines states they can practically make the same power but it's usually coming much later in the RPM range.

Another gas option is going up to a 520 HP merc racing model, which takes the cat's out of there but I think otherwise it's just as complex and even less common (although maybe the same basic setup as the 8.2 HO).

Thanks!

Jon

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iTrader: (9)

things that hurt or kill the CAT - run the engine out of gas, Misfires and the many ways misfires can take place, heat an overly hot running the engine or too much heat in the exhaust system, to cold of a running engine, NOT using the recommended silicone and gasket sealers, fiberglass fine shaving in the fuel, bad gas, Water reversion, Leaking exhaust internally.

Finding a mechanic that really knows how to work on these newer mandated emission controlled engines and then one who knows this newer 8.2 is prob the hardest part of owning one.

Don t get me wrong there is some positive sides of owning a CAT engine as well.

leaky

Thanks again for that! Any idea on what other engine you would look at? Like Indmar or something?

I've been maintaining a set of Opti's for the last 10 years, just to give me an idea, do you figure they are harder to trouble-shoot than Opti's?

I feel like I may be between a rock and hard place. The only other new engine options I see other than a rare make like Indmar, or by going to much smaller HP/torque/displacement, is to a diesel... And that's got a new set of questions/downsides including very recent Tier III diesel designs that are likely less deployed than the 8.2 merc, and of course the bobtail engine $$ goes from ~20K to ~40K. For sure it'd burn less fuel and last longer but service likely will not be any easier either with the latest & greatest computer computer controlled diesel.

The friend of mine (who I was really approaching for a quote) was advocating going back to slightly older technology, ie like a crusader big block MPI, but I'm pretty sure they are only getting stricter about enforcing these laws so am hesitant to do so.

Jon

CIG3

I really like the Ilmor offerings. One point is they also offer their own drive system for their LS based engines. I've had nothing but good experiences with them on (3) installs.

http://www.ilmor.com/en/marine/recre...px?menu_id=406

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iTrader: (9)

ILmor drives are Yanmar drives in which basically are the older Yamaha Hydra drives internally. Not saying they are bad.

Volvo would be a good choice as well paired to a Volvo DP drive, The weak link with Volvo's is the external mounted trim pumps in the transom assembly.

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iTrader: (9)

this I say more so.

http://www.ilmor.com/en/marine/recre...px?menu_id=416

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iTrader: (9)

But more so would take this any day link below - not taking away from ILmor by any means but Volvo is on their 3 rd year with GDI plus more dealer base 40 to 1 over Ilmor. That includes parts and service wise.

Also more certified techs on the Volvo side. Just saying as I do like all Ilmor products as well but Volvo DP outdrive is very hard to beat that twin prop and their nil Cat problems is the better end.

http://www.volvopenta.com/volvopenta...es/V8-430.aspx

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iTrader: (9)

https://books.google.com/books?id=pB...0drive&f=false

I am pretty sure Yanmar has this from Yamaha