Marinette Boat Forum

Check out Michigan Motorz they offer turn-key EFI engines. Spoke in depth with them, unless your just hell bent to go with EFI I'd stay with carbed and change over to a small block Chevy. A little extra work but if your in for the long haul, that would be the way to go, IMHO.

Zirconia O2 sensors are only used for effective use of the catalyst. If working properly the pre catalyst O2's "switch" constantly from lean to rich and rich to lean. Wide band sensors found in newer cars and racing applications have a much wider accurate range of air fuel ratios from about 12:1-18:1. Only Catalyst equipped marine engines use O2's which is 2011 and up new boats approximately. Just because its open loop doesn't mean there aren't advantages. EFI open loop is much cleaner and efficient than a carburetor. Hence, the whole 1,2,3,4,5 star marine ratings that the EPA came up with for marine use. If you look at engines built in the last 15 years or so you will see that they have a"star" rating. Obviously, just like vehicles, the emission requirements get tougher as the years go by. I repowered two 37ft Big M's in 2003. Took out 440's and installed 375hp 8.1L Crusader's. Both customers comment still to this day that the boat is more fuel efficient and faster than when the boat was new. You would think that more CID and more HP would eat more fuel. At wide open throttle probably, but cruising speed it won't if propped correctly. The engines aren't working as hard at cruising speed than the 440's were, and the EFI takes full advantage of the engine's potential. Open loop engines run just fine and in the early years of EFI in vehicles most manufacturer's idle in open loop. It was more stable without the fuel correction closed loop setup. ECU's are much faster today, emissions are tougher, and basically vehicles are in closed loop within seconds on a cold startup.

I replaced a frozen engine with a long block replacement. It was a big mess. The mechanic ordered the wrong rotation and talked me into converting it. The expensive manifolds had to be replaced and the bolt-ons from the old engine were mostly crap. I told the guy to replace bad parts not put them on the new block first - he didn't listen. The engine should have been built and test run on the garage floor not in the hold. I was pulling cigarette buts and beer cans out my hold for weeks after the engine was redone. My experience was a nightmare. I ended up buying another boat with good low hour engines. Used boat prices make taking on a project boat not a very economical choice. It better be a labor of love. I wouldn't even know where to start with an auto engine. After I went through my engine replacement, I found several places on-line where the mechanics built up entire marine engines from long blocks and had Youtube videos of them running like clocks on the shop room floor. That is the way to go.

Damn right they should be test run on the shop floor. I ran mine for at least a half hour.

Jeff

yooper wrote:I replaced a frozen engine with a long block replacement. It was a big mess. The mechanic ordered the wrong rotation and talked me into converting it. The expensive manifolds had to be replaced and the bolt-ons from the old engine were mostly crap. I told the guy to replace bad parts not put them on the new block first - he didn't listen. The engine should have been built and test run on the garage floor not in the hold. I was pulling cigarette buts and beer cans out my hold for weeks after the engine was redone. My experience was a nightmare. I ended up buying another boat with good low hour engines. Used boat prices make taking on a project boat not a very economical choice. It better be a labor of love. I wouldn't even know where to start with an auto engine. After I went through my engine replacement, I found several places on-line where the mechanics built up entire marine engines from long blocks and had Youtube videos of them running like clocks on the shop room floor. That is the way to go.

Sorry to hear of your problems, that was an expensive and frustrating lesson. I can see that the problem was you did not have a mechanic, you had an idiot that said he was a mechanic.

Busia wrote: I can see that the problem was you did not have a mechanic, you had an idiot that said he was a mechanic.

Very common problem for many car/boat/equipment owners. The bad thing is, these guys put a bad taste in a potential customers mouth even towards the techs who are good, and know what they are doing.

Regarding using a automotive engine... I've heard that spark & gas vapor control is a major safety concern. Maybe fuel injection takes care of the vapor concerns. Starter, alternator, distributor, and many other engine electrical components can still be a problem.
And I've heard that marine engines are setup to run better under the heavy load (maybe cam, lifters, heads, etc).
Others here certainly know a lot more than me about this subject.

For many of us our age and ability force us to have the work performed. This is a major expense and before you hire a "Mechanic" or yard to do the work... INSIST on a list of customers who they have repowered boats and contact as many as you can. You may be surprised on their real time reviews.


safe harbors