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    Distributor advance curve for a heavy boat

    Scott, what does BMEP mean? Max rpm for this MIE 330 is spec’d at 3800-4200 rpm in the service manual. My WOT is 3850 rpm turning a 19x17 3-blade prop on the 2:1 V-drive. The manual gives a min and max advance curve that gives the range for this engine. Total spark advance minus initial...
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    Distributor advance curve for a heavy boat

    My 26ft Tollycraft is running fine with the single Mark IV 454 on a 2:1 V-drive, but I’m wondering if I can improve performance by adjusting the advance curve on the distributor? This is a 10,000 lb flybridge cruiser, 26’8” LWL, 10’ beam, runs at 7 knots at 1700 rpm most of the time, or 14...
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    RPMs surging, smell of fuel in exhaust

    This just started recently, rpms occasionally surging up/down 100 rpm at 2000 rpm slow cruise, occasional smell of gas in exhaust, especially when reducing throttle, engine sounds a little rough, not purring. Vacuum readings at 2000 rpm are rock steady. Quadrajet carb on a 454.
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    Freshwater flush after seawater use?

    My inboard has closed cooling but the exhaust elbows are seawater cooled and need to be replaced every 4 years. If I plumb a connection to my 40 gal water tank I could easily rinse them with freshwater after every trip. Besides the expense of doing this properly with bronze fittings etc, plus...
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    Intake valves black, should I clean?

    So I have my intake manifold off on my 1977 Mercruiser MIE 330 s/n 5551947 and can see the intake valves through the air intake ports. They are all pretty black and crusty looking (except for the one getting washed by a coolant leak - I'll fix that). While I'm in there should I spray something...
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    Coolant smell in exhaust on start

    I've been loosing coolant every time out, about 200 ml or so, with no sign of leaks on the engine. I noticed a smell of coolant on start up for a few seconds and some white smoke. No sign of milky oil on the dipstick. I removed the distributor and see coolant on top of the block near the...
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    Slave solenoid terminals labelled I and S

    Replacing my slave solenoid and the new one looks similar to the old except the two small terminals have a letter I and S beside them. What could this mean? Does it matter which one gets the ground ?
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    OK to bypass circuit breaker?

    Dewinterizing the boat and have a no start scenario with my 1977 MIE 330. First try starter engages then quits. Second try, nothing at all Check all connections, poke the circuit breaker button, not popped Third try slave solenoid clicks, but no starter action Could this be due to a faulty...
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    GM 7.4L?

    I thought GM stopped making the 7.4 in 1999. Mod EDIT: Finnerty, a mod removed your previous topic. Please dont link competitors urls on the forum sponsored by iboats. Please refrain from posting their info again. And take a minute to review the forum rules and guidelines. Thanks John
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    Prop to top, bottom or middle of rpm range?

    My Mk3 7.4L is spec'd max 3800-4200 WOT It powers a heavy (10000 lb) single shaft v-drive planing hull Current 19X18 3b prop gives 22.5 knots WOT at 3850. It was suggested to me that I may be lugging the engine running it at a 3200 cruise(16 knots) with this prop . I'm considering a reprop to...
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    Transmission ratio makes BB = SB?

    Planning for an eventual repower and wanting to go SBC to replace BBC (stay calm): If a BBC 330 HP cruises at 3200 rpm peak TQ 420 with a 1.99 ratio that's 835.6 Prop TQ If a SBC 330 HP cruises at 3200 rpm peak TQ 370 with a 2.47 ratio that's 913.9 Prop TQ Why not go with a small block?
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    Need full tabs to plane, go 4 blade?

    My boat is a 26 Tollycraft flybridge cruiser 10000 lbs, single 454 V-drive 1.99:1 reduction This is a 1977 Mercruiser WOT spec range 3800-4200 rpm I've got room for a max 19" diameter prop Original 19X20 3-blade gave WOT 3700 (too low) I repitched: Now 19X18 3-blade gives WOT 3850 (better) It's...
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    Availability of non-catalytic gas engines? in Canada?

    Looking at a repower and my Canadian Mercruiser dealer said that at some point in the future we will no longer be able to buy non-catalytic converter gas engines. I've heard that the ECT version gas inboards are more expensive and trouble-prone. Anyone know when? What's the case in the US?
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    Mallory Distributor Number 1977 MIE 330

    Having recurring problems with my electronic ignition system at fast cruise, and have done everything I can think of, so starting back at square one to make sure I have the correct Petronix Ignitor for my 1977 Mercruiser MIE 330 (S/N 5551947L). Petronix tech support says they need the...
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    Finding the correct replacement coil?

    My local Mercruiser mechanic suggested I replace my Blue Streak coil as it was not suited for my engine. Problem is that we have tried two different coils (PerTronix 40,000v and another brand I can't remember) and they both produce the same result, only starts at high rpm and stalls below 1700...
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    SS crevice corrosion..what else to use?

    Removed the stainless steel screws to replace the stainless steel trim tabs on my boat (which is kept in saltwater) and discovered the shaft of the screws were almost entirely eaten away. Apparently this is not electrolysis but is crevice corrosion that occurs in pockets of stagnant (no oxygen)...
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    How to remove "glued-on" trim tab mounting plates?

    I need to remove my old trim tabs but they are stuck on my fiberglass hull with who-knows-what, maybe 5200 or epoxy. Before I resort to grinding them off with an angle grinder or attacking them with a chisel I was wondering if I could heat them up with a torch or with a heat gun to help loosen...
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    Changing pitch vs changing diameter - what effect gear reduction?

    If a 2 inch change in pitch with a 2:1 gear reduction caused a 150 rpm change in WOT, would a 1 inch change in diameter give roughly the same result (assuming a 1 inch change in diameter is similar to a 2-3 inch change in pitch) or in this case because of the 2:1 reduction would it double the...
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    Removing seized SS screws from aluminum

    What are the options for removing SS screws from corroded aluminum? I want to remove an aluminum angle bar from the transom of my fiberglass boat (used to support the swim platform) that has been screwed into the hull using SS screws. I tried heating the screws with the tip of a soldering iron...
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    Repower needs bigger exhaust ports?

    I'm looking at replacing my 1977 vintage 454 with a small block and they require a 3.5" or 4" exhaust depending on the make. Replacing hoses and mufflers is easy enough but this requires that I replace the two existing 3" exhaust ports through the transom with the specified larger ones. Have I...
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