So my buddy just got a free boat. (I know, there is no such thing as a free boat. He will learn.) Only major issue is that it won't start. 
I took a quick look at it in the dark, and there are a ton of things to check (it was stored the last 10 years) but here's the one odd thing. Spraying starting fluid directly into the carb when cranking does nothing, No surge at all. He said it has spark and fuel, so how can that be?
I believe to start a boat you call up the yacht club and you ask one of the stewards to have it ready for your arrival at 5:00pm.
1st... never start a boat without the prop in water.
next question.....2 cycle or 4 cycle?
It looks likes the old Iron Duke 4-Cylinder to me, in the dark.
Some research shows that it is a Mercury 3.0.
pinchvalve wrote:So my buddy just got a free boat. (I know, there is no such thing as a free boat. He will learn.)
I'm sure everyone knows that a boat is a hole in the water that you put money into.
You can simulate boating by standing in a cold shower ,wearing your clothes and tearing up $100 bills.
Did someone say Motorboating?
pilotbraden wrote:You can simulate boating by standing in a cold shower ,wearing your clothes and tearing up $100 bills.
LOL! 
This should help you. Its a pretty good summarization for how to start most boats. YMMV.
half the boat owners i know basically have them as floating platforms they use for drinking beer next to a dock.
the other half regularly leave the house at 3am to go tuna fishing.
it seems like there should be a happy medium in there somewhere.
have you tried coasting it down a river and popping the clutch in first?
Joking aside, assuming that the cranking RPM's suggest good compression I'd suspect bad gas or a clogged air induction system.
+1 on bad gas, but starting fluid should do it. Fluid plus spark should equal fire, but what do I know about boats. Sitting for all that time can screw up a lot of things. Just for giggles, pull the engine and give it a redneck rebuild.
I think we are going to put it in the water with a full cooler, and ponder the issue while we float around.
That engine is basically the Iron Duke. Mercury just did the conversion. My boss had one many years ago. Just because it is in a boat doesn't make it any different as far as trouble shooting. Lack of fire with starting fluid would indicate no spark or lack of compression.. 10 yrs. of storage can create a lot of problems.
You can probably run a Mercury I/O for about 10 seconds out of the water. That is enough time to see if it fires.
The big deal is, a boat is not like a car when you are dealing with gasoline. Boats blow up ALL the time because the vapors go into the bottom of the boat, not on the ground.
So, like others said, its just a car motor. It probably has points that are fried from the key being left on. Clean them up, and then just hotwire the thing for testing.
Do not spill gas in the boat. If you do, run water down and out the little hole in back to get rid of the fumes, and then go do something else.
Jay Morris
well... always start to fill the tank WITH the exhaust fans running. They should also PUSH air into the bilge instead of pulling it out.
If the engine has spark, I am betting the rings are frozen and you have no compression. Time for some seafoam?
pinchvalve wrote:I think we are going to put it in the water with a full cooler, and ponder the issue while we float around.
i think you are on the right track.
In my rotary world, I get a clear understanding of compression just by cranking over the engine as the RPM's will be around 40% higher with one chamber blowing and around 80% higher with both chambers blowing...you don't even need to look at the tach, your ear can easily tell the dirrenence between both good, one down, & both down.
I realize you piston guys have a much harder job as you've got as many as eight "chambers" to deal with so the RPM shift will be much less pronounced.
Silly piston guys, compression testers are just ETTF (Estimated Time To Failure) indicators.
RX Reven' wrote:Silly piston guys, compression testers are just ETTF (Estimated Time To Failure) indicators.
I do happen to have the bell-housing one would need to install a rotary as an inboard boat motor, if it makes boating more exciting for you...
^ I've been wanting some sort of rotorboat, but I need another time-consuming hobby like I need a hole in my head.
This is the only boat I consider.
My boat story, I bought my grandfathers boat that had sat for 10 years off of him for $1. It is a 15ft fiberglass hull with a johnson 65 outboard built in 1971. Got it to sputter on starting fluid and decided to take the easy out with the boat shop. $500 in new carburation later it runs pretty reliably. (not perfect, but comon, 1971..)
Right now the to do list is this,
Figure out where the oil that seeped out over the winter came from
Take outboard off and reenforce the transom (gonna sandwitch it with Aluminium plates)
paperwork
sell organs to pay for gas, go catch lots of fish
Mercury, or MerCruiser? One is an outboard, one is an inboard/outboard (I/O). If it's a Mercury outboard, I can't help. MerCruiser I/Os on the other hand, been there done that.
Ignition on an I/O is just like a car with one exception. I/O engines have a shift interrupter switch that kills the ignition for a split second while the transmission is shifting from neutral to forward or reverse. This switch is usually on the shift/throttle plate mounted on the starboard (right) side of the engine. They will get out of adjustment and can fail. If the usual culprits don't turn up anything I would check the shift interrupter switch. It is also pretty easy to hot wire a boat. A jumper from the battery to the coil will tell you if the problem is engine related or in the boat wiring. If you bypass the switch, don't forget the tie it back in. A rebuilt MerCruiser foot, where the transmission is, costs in the $1500+ range. You don't want to tear it up over a $20 switch.
Don't use car parts on a boat. Particularly the carburetor, distributor, starter and alternator. Automotive parts aren't sealed to prevent explosions like marine parts. They are a little more expensive, but then being blown up isn't cheap either.
DO NOT run it without supplying water to the foot either through ear muffs or by putting the boat in the water. It will wipe out the rubber water pump impeller in the foot. It is water lubricated. I would also consider changing the pump impeller also. After sitting for 10 years it is probably rather stiff. I usually put a kit in mine every other year. It's cheap insurance.
Another thing, most MerCruisers have a resettable circuit breaker on the engine as well. Check and make sure it is not tripped. It usually shuts down the starting control circuit as well, but maybe not in your case.
Added to remind you what your friend is getting into. 
B.O.A.T. Break Out Another Thousand.
Keep in mind, the best two days of a boat owners life are the day he gets it and the day he sells it.
oldopelguy wrote:RX Reven' wrote:Silly piston guys, compression testers are just ETTF (Estimated Time To Failure) indicators.
I do happen to have the bell-housing one would need to install a rotary as an inboard boat motor, if it makes boating more exciting for you...
Would you happen to have the manifold as well. Would you like to sell it. Shoot me a pm if so.
