Way Off Topic - Boat Motor Assist Please.

Beware of the dealers who perpetuate the myth of "marinised" parts. I used to go boating on a 24ft cruiser with a Volvo inboard/outdrive. four cylinder, basically a 145 engine. we replaced a water pump and an alternator, did regular oil and filter changes, and found out after checking part numbers, that there are two different sets of part numbers and two hugely different prices for identical parts. The "marinised" alternator was £350, but the car equivalent was £130! even the brush/diode pack was identical, but had a different part no. The give away was the bearings, two different part numbers, two different prices, but the same manufacturers number on the bearings. A boat is a hole in the water that you throw money into! They know it, and they screw you! As to the duty cycle being tougher, I cannot see how using an engine to power a boat at 4000rpm is any different to charging down the autobahn at 100 miles an hour. Bought a dozen oil filters wholesale, for a citroen 2cv, found out that the identical filter fits a Ducati v twin! then checked the price list for Ducati v twin! three times that for a 2cv. and thats how they make their money, and why they ask "whats it for" rather than, do you have a part number!
Phil
 
Boat motors of built to operate at wide open throttle hence 100% duty cycle. Automobile engines are not rated that high. As for driving 100 mph try doing that in first gear at wide open throttle and see how long that engine will last. Boats do not have multiple gear transmissions. That being said I have seen even up swaps with diesel engines hold up. An alternator does not go through the stress of the motor. But I do agree they are a place to part with any extra cash you might have had!
 
you cannot drive any engine flat out if that means exceeding the maximum rpm the engine is designed to do, that was my point, 4000rpm is the same in a car or a boat, we used to water ski behind a speedboat with a 1600cc marinised ford engine, how was it marinised? you fitted a water cooled manifold, the rest was bog standard car engine. we had two of them, all aluminium "albatross" speedboats with 2 skin cooling panels in the bottom of the hull. would pull 2 skiers at a pinch. great fun, but not much freeboard, so dodgy in rough weather. Lake boats really, but we water skied Bridlington bay in them, bit hairy in the swell!
 
X2 - Unless your talking about racing boats the I/O engines are pretty much straight across car engines with maybe a slightly different cam profile. Nothing fancy there at all. GM replacement long blocks are around 2k. As said you can pay a lot more purchasing from a marine dealer, but your getting the same thing, except maybe brass core plugs. They do work harder, but your talking pretty moderate rpm once up on plane and generally way fewer hrs than you see in automotive use. Mike
 
Beside water jackets, the biggest difference is the oil pan. Usually lager capacity with baffles but as already said the same for the most part as street applications.
 
I believe marine engines are spark proofed , sealed alternaters , distributors , wires ,
 
dlane said:
I believe marine engines are spark proofed , sealed alternaters , distributors , wires ,
Click to expand...

The penta I/O we used were not at all spark proofed, and we know the parts we took off were "marine" by the part numbers. We looked at a £350 "marinised" alternator but didn't buy it because it was obvious that it was not in any way marinised, just a standard Volvo automotive replacement. I am not saying this is always the case, I am just saying, be aware and check! you can save a lot of money! To be honest petrol (GAS) inboard engines are not as popular in the UK as they are in the US. I well remember how it made me a bit nervous and I always used to be first up to run the engine box fan . I much prefer bigger boats with twin diesels! Just don't have the money for it today.
 
Mercury marine I/o engines are / were , at least the ones I owned 10+ years ago , they have probably gone downhill like most other companies.
Don't know about the imports.
 
dlane said:
Mercury marine I/o engines are / were , at least the ones I owned 10+ years ago , they have probably gone downhill like most other companies.
Don't know about the imports.
Click to expand...
Don't know about that one. When my buddy and I tore down the twin 350's out of his 1984 Scarab a few years ago, the motors were
the same as what you would find in a vehicle of that era. He needed the heads replaced on one and I scrounged a set off a Chevy
van and had them reworked at a local speed shop.
Before taking them in I compared the valve train, and could find no difference besides the part numbers.
"marinised" I do believe is myth.
On our old bowrider, the motor in it is the _OLD_ style 4-banger GM industrial purposed motor. So yes, whether it is a boat,
or a generator or a water pump it is ran at the max RPM allowed.
But on my buddy's Scarab those are just automotive motors with Merc badges and costly part numbers to go with them...

BOAT - Break Out Another Thousand....
 
hermetic said:
Beware of the dealers who perpetuate the myth of "marinised" parts. I used to go boating on a 24ft cruiser with a Volvo inboard/outdrive. four cylinder, basically a 145 engine. we replaced a water pump and an alternator, did regular oil and filter changes, and found out after checking part numbers, that there are two different sets of part numbers and two hugely different prices for identical parts. The "marinised" alternator was £350, but the car equivalent was £130! even the brush/diode pack was identical, but had a different part no. The give away was the bearings, two different part numbers, two different prices, but the same manufacturers number on the bearings. A boat is a hole in the water that you throw money into! They know it, and they screw you! As to the duty cycle being tougher, I cannot see how using an engine to power a boat at 4000rpm is any different to charging down the autobahn at 100 miles an hour. Bought a dozen oil filters wholesale, for a citroen 2cv, found out that the identical filter fits a Ducati v twin! then checked the price list for Ducati v twin! three times that for a 2cv. and thats how they make their money, and why they ask "whats it for" rather than, do you have a part number!
Phil
Click to expand...

Careful... Look up "ignition protected"
 
You must log in or register to reply here.
Back
Top