Patriciah22a
Cadet
- Joined
- Feb 18, 2013
- Messages
- 10
First and foremost thanks to all of the members on this forum that have provided invaluable information for my prior research, I am convinced I've leeched dozens of hours of reading and for the most part it was extremely helpful. I hope I can give back to the community in the long run.
Here's my synopsis. 1996 Maxum SCR2400 with mercruiser I/o 5.7 2bb carb. I am a mechanic and am prepared for the worst.
The boat was purchased last summer, it ran at this time, poorly, but ran nonetheless (starting became exceedingly difficult and required a substantial amount of throttling and excess rotations before it considered starting). Finally I was unable to start the boat but my persistence resulted in a seized starter solenoid. Due to the nature of my emergency a cardinal rule of boat mechanics had to be broken: I installed an automotive starter matching the Chevy 350 configuration. This got me back to my previous stage of "barely starting" (the automotive starter was missing one of the terminals - I suspect this lead was for the coil if memory serves me, I bypassed this with a switched hardwire to a constant 12v source). The boat at this point ran hot. After a proper overnight cool down and replacing the overflowed coolant i attempted to start it again. (No coolant in oil, no evidence of blown headgasket). Wouldn't start as expected. Decided to inspect the cap and rotor - they looked extremely worn so I replaced them. This didn't result in a start (just a semi-healthy crank). I had to abandon ship (literally) and come back to home (2 hours away from the beach where I keep the boat). I had a local boat mechanic swing by to check on the boat. After a bit of diag he noticed my wire order was off on the cap (must have happened when I installed the new cap/button). He said it fired up instantly with no throttle assist and idled perfect but it would run hot shortly after. It never left the dock at this point. I returned to the boat to move it back to dry storage the following night. Sure enough the boat effortlessly fired all 8 with the bump of a key in a Lexus-like fashion; while trying to understand how this miracle occurred I watched the temp gauge climb. This confirmed two things - 1, I made a good call on the cap/rotor needing replacing, 2 that I was still dealing with an overheating issue. I decided to diagnose the cooling system on dry ground which I wasn't too familiar with - when attempting to inspect the lower unit pump it turns out to my surprise I didn't find a damaged impeller, rather it was missing altogether - yes, someone actually removed it and reassembled the housing ((the mismatched 4 housing bolts were an indicator of the past maintenance history of the boat)) so just a shiny shaft with no signs of a past impeller OR key way. I purchased all new components and proceeded with proper servicing protocols. I inspected the raw water pump also and found all impellers missing from damage, I also replaced this along with a new housing. Now with excitement I put the boat in the water - yet again a perfect start and smooth idle with no hi-temps. I thought I conquered the world and loaded my rods and bait with a huge grin on my face. The moment I engaged reverse the boat died. Of course this was the result of a shift cutout switch being slightly out of alignment. No problem, return to neutral and try to fire, NILL. Back to square one, the prolonged turning over yet this time it yielded no result. No start, just an endless crank. I towed the boat back to my shop in Raleigh and decided to proceed with a mild ignition overhaul. I tried starting it with muffs and eventually got it to fire but this involved starting fluid and was by no means the Lexus start i was previously spoiled by. Gameplan in effect: New plugs, new coil (Accel??), carb rebuilt (Rochester 2bb). Lake test had poor results - no start. I wasn't equipped to diagnose spark but at this point anything is possible and it may have been missing. Fuel was surely present. After further diagnosis with the company of a fellow boater we were yet again able to fire it up straneously on muffs, this confirmed we had spark and fuel. Minutes later I noticed oil (mixed with fuel) coming from the dipstick!!! My crank case had filled with a mixture of oil and fuel now. I attributed this to the hour long attempts to crank whilst not having spark. Project on hold. Decided to inspect the mechanical fuel pump for a ruptured diaphragm and of course replace the crank case content with fresh oil and a touch of Lucas. I spent another 10 hours tracking down wiring and finally ensuring the coil was getting the proper signal and sending a spark to the distributor. Confirmed perfect alignment of cutout switch and proper ohming results. I even temporarily bypassed for diag sake to get the boat fired up. I inspected the ignition sensor (under the rotor button and while it looked rough, it all appeared to be correct with both (maybe 3) resistors intact. This unit has two wires - white/red and white/green. I found a lose ground in the vicinity and added it to one of the cap screws in line with this sensor (alternate online part generic searches showed a consistent presence of a ground wire, this all appeared to be proper. I tested the modules that allow for testing (tapping white/green wire to ground repeatedly to check for spark at coil, confined blue arch). I then confirmed spark is present at distributor points. Fuel pump took awhile to prime after reassembly, but proved to function properly. So at this point I had fuel and spark, what more do you expect from a 350?! Random backfire in the carb and no start resulted in yet again second guessing my firing order. Intake is stamped clearly with the 1-8-4-3etc order and all cylinders are labeled. Since the cap had no markings, I did some brief googling and found most suggestions that cyl #1 would be in the 5 I clock position. I corrected this order (that my boat friend that had recently helped me work on the boat when the oil/gas/dipstick happened, he decided to revisit my firing order, I had to many beers at this point to remember why be changed it or if he even did) according to the diagrams found online assuming I has the right location of cylinder 1. This again resulted in backfire and no start. Hours of pointless diag later, I pulled the cap off and bumped the motor to tdc (I assume its what it was at when I lined up the block marking with the crank pulley groove). The rotor button pointed to cyl 1 being one over from what I had previously assumed. Excited and hopeful Moved the rotation over 1 and expected results. None whatsoever... Perhaps no backfire in the carb but no start. At this point I hang my hat up. Quick recap, I have fuel and spark (at least to dizzy points - I didn't have a 3/4 plug socket to pull the plugs and confirm spark, and to be honest I don't know that I checked for spark on the plug end of my wire... I was delirious at this point and the fuel fumes were grossly at fault). Next step would have been to check spark at plugs to eliminate the possibility of my wires magically and randomly failing and to see if the new plugs were fouled completely by the new persistent attempts to fire. Safety switch is jumped to eliminate from the equation. Tach wire removed from gauge to eliminate coil short to ground. Cutout switch functioning correctly. Main round engine harness checked (to the best of my ability) and proved not to be faulty. Prior to making this post I read a thread of someone with a random no start issue claiming the rotor button tab sheared off resulting in a random spinning, last I roved it it appeared intact and it didn't require force for reassembly. Ignition switch showed functioning leads in proper rotation (red/blue power and start 1 & 2 being purple and yellow/red ((this is all from memory so don't hold me to it))). I am questioning a possible engine ground??? No reason to believe this is at all possible as all connections appeared intact and all 12v connections checked out with proper multimeter readings using existing engine grounds.
I realize this has to be the most outrageous forum post ever and I hope I didn't violate any rules by posting this. If nobody reads this I totally understand and I also would be overwhelmed upon clicking this thread if I stumbled upon it. I also apologies for typos and various misuse of terminology (ie. cranking). I also may have possibly submitted this post earlier on prior to finishing which surely would throw someone off, I have written this on my phone while having the wife drive us home from the beach. Another quick note, the boat was freshwater kept until I took possession of it and put it in the ocean. It is kept in dry storage when not in use. I also want to point out this boat belongs to my clueless and helpless parents so all of the hours and money invested will never see a proper return. You may ask why I tackled this nightmare and I will tell you (with regrets) that I saw a challenge and thought I could defeat it; bad idea. I also have zero marine mechanical knowledge, my only prior marine experience was owning a 05 Air Nautique with 80 hours on it that required ZERO maintenance during my ownership. I am a self-proclaimed mechanic, rather a SUPER HARD CORE CAR GUY - I own a shop but no longer have any real hands on involvement, rather I diagnose problems and let others bust their knuckles, I do however take pride hands on when it comes to my supercharged z06, big turbo Audi S4, 4 rock crawler fully built jeeps, bike, etc - toys offer a level of reward unlike anything else. Keep in mind this failed boating diagnosis has been humbling for several reasons but primarily because my trusting wife has been supporting me in time and emotion along the way with no results. If you are still reading (you're crazy!), please offer suggestions. This post was only this long from the get-go to eliminate dozens of other posts where I'd have to clarify my process thus fad. I hope this will eventually not only lead to a result for me but also provide useful information for future readers.
Here's my synopsis. 1996 Maxum SCR2400 with mercruiser I/o 5.7 2bb carb. I am a mechanic and am prepared for the worst.
The boat was purchased last summer, it ran at this time, poorly, but ran nonetheless (starting became exceedingly difficult and required a substantial amount of throttling and excess rotations before it considered starting). Finally I was unable to start the boat but my persistence resulted in a seized starter solenoid. Due to the nature of my emergency a cardinal rule of boat mechanics had to be broken: I installed an automotive starter matching the Chevy 350 configuration. This got me back to my previous stage of "barely starting" (the automotive starter was missing one of the terminals - I suspect this lead was for the coil if memory serves me, I bypassed this with a switched hardwire to a constant 12v source). The boat at this point ran hot. After a proper overnight cool down and replacing the overflowed coolant i attempted to start it again. (No coolant in oil, no evidence of blown headgasket). Wouldn't start as expected. Decided to inspect the cap and rotor - they looked extremely worn so I replaced them. This didn't result in a start (just a semi-healthy crank). I had to abandon ship (literally) and come back to home (2 hours away from the beach where I keep the boat). I had a local boat mechanic swing by to check on the boat. After a bit of diag he noticed my wire order was off on the cap (must have happened when I installed the new cap/button). He said it fired up instantly with no throttle assist and idled perfect but it would run hot shortly after. It never left the dock at this point. I returned to the boat to move it back to dry storage the following night. Sure enough the boat effortlessly fired all 8 with the bump of a key in a Lexus-like fashion; while trying to understand how this miracle occurred I watched the temp gauge climb. This confirmed two things - 1, I made a good call on the cap/rotor needing replacing, 2 that I was still dealing with an overheating issue. I decided to diagnose the cooling system on dry ground which I wasn't too familiar with - when attempting to inspect the lower unit pump it turns out to my surprise I didn't find a damaged impeller, rather it was missing altogether - yes, someone actually removed it and reassembled the housing ((the mismatched 4 housing bolts were an indicator of the past maintenance history of the boat)) so just a shiny shaft with no signs of a past impeller OR key way. I purchased all new components and proceeded with proper servicing protocols. I inspected the raw water pump also and found all impellers missing from damage, I also replaced this along with a new housing. Now with excitement I put the boat in the water - yet again a perfect start and smooth idle with no hi-temps. I thought I conquered the world and loaded my rods and bait with a huge grin on my face. The moment I engaged reverse the boat died. Of course this was the result of a shift cutout switch being slightly out of alignment. No problem, return to neutral and try to fire, NILL. Back to square one, the prolonged turning over yet this time it yielded no result. No start, just an endless crank. I towed the boat back to my shop in Raleigh and decided to proceed with a mild ignition overhaul. I tried starting it with muffs and eventually got it to fire but this involved starting fluid and was by no means the Lexus start i was previously spoiled by. Gameplan in effect: New plugs, new coil (Accel??), carb rebuilt (Rochester 2bb). Lake test had poor results - no start. I wasn't equipped to diagnose spark but at this point anything is possible and it may have been missing. Fuel was surely present. After further diagnosis with the company of a fellow boater we were yet again able to fire it up straneously on muffs, this confirmed we had spark and fuel. Minutes later I noticed oil (mixed with fuel) coming from the dipstick!!! My crank case had filled with a mixture of oil and fuel now. I attributed this to the hour long attempts to crank whilst not having spark. Project on hold. Decided to inspect the mechanical fuel pump for a ruptured diaphragm and of course replace the crank case content with fresh oil and a touch of Lucas. I spent another 10 hours tracking down wiring and finally ensuring the coil was getting the proper signal and sending a spark to the distributor. Confirmed perfect alignment of cutout switch and proper ohming results. I even temporarily bypassed for diag sake to get the boat fired up. I inspected the ignition sensor (under the rotor button and while it looked rough, it all appeared to be correct with both (maybe 3) resistors intact. This unit has two wires - white/red and white/green. I found a lose ground in the vicinity and added it to one of the cap screws in line with this sensor (alternate online part generic searches showed a consistent presence of a ground wire, this all appeared to be proper. I tested the modules that allow for testing (tapping white/green wire to ground repeatedly to check for spark at coil, confined blue arch). I then confirmed spark is present at distributor points. Fuel pump took awhile to prime after reassembly, but proved to function properly. So at this point I had fuel and spark, what more do you expect from a 350?! Random backfire in the carb and no start resulted in yet again second guessing my firing order. Intake is stamped clearly with the 1-8-4-3etc order and all cylinders are labeled. Since the cap had no markings, I did some brief googling and found most suggestions that cyl #1 would be in the 5 I clock position. I corrected this order (that my boat friend that had recently helped me work on the boat when the oil/gas/dipstick happened, he decided to revisit my firing order, I had to many beers at this point to remember why be changed it or if he even did) according to the diagrams found online assuming I has the right location of cylinder 1. This again resulted in backfire and no start. Hours of pointless diag later, I pulled the cap off and bumped the motor to tdc (I assume its what it was at when I lined up the block marking with the crank pulley groove). The rotor button pointed to cyl 1 being one over from what I had previously assumed. Excited and hopeful Moved the rotation over 1 and expected results. None whatsoever... Perhaps no backfire in the carb but no start. At this point I hang my hat up. Quick recap, I have fuel and spark (at least to dizzy points - I didn't have a 3/4 plug socket to pull the plugs and confirm spark, and to be honest I don't know that I checked for spark on the plug end of my wire... I was delirious at this point and the fuel fumes were grossly at fault). Next step would have been to check spark at plugs to eliminate the possibility of my wires magically and randomly failing and to see if the new plugs were fouled completely by the new persistent attempts to fire. Safety switch is jumped to eliminate from the equation. Tach wire removed from gauge to eliminate coil short to ground. Cutout switch functioning correctly. Main round engine harness checked (to the best of my ability) and proved not to be faulty. Prior to making this post I read a thread of someone with a random no start issue claiming the rotor button tab sheared off resulting in a random spinning, last I roved it it appeared intact and it didn't require force for reassembly. Ignition switch showed functioning leads in proper rotation (red/blue power and start 1 & 2 being purple and yellow/red ((this is all from memory so don't hold me to it))). I am questioning a possible engine ground??? No reason to believe this is at all possible as all connections appeared intact and all 12v connections checked out with proper multimeter readings using existing engine grounds.
I realize this has to be the most outrageous forum post ever and I hope I didn't violate any rules by posting this. If nobody reads this I totally understand and I also would be overwhelmed upon clicking this thread if I stumbled upon it. I also apologies for typos and various misuse of terminology (ie. cranking). I also may have possibly submitted this post earlier on prior to finishing which surely would throw someone off, I have written this on my phone while having the wife drive us home from the beach. Another quick note, the boat was freshwater kept until I took possession of it and put it in the ocean. It is kept in dry storage when not in use. I also want to point out this boat belongs to my clueless and helpless parents so all of the hours and money invested will never see a proper return. You may ask why I tackled this nightmare and I will tell you (with regrets) that I saw a challenge and thought I could defeat it; bad idea. I also have zero marine mechanical knowledge, my only prior marine experience was owning a 05 Air Nautique with 80 hours on it that required ZERO maintenance during my ownership. I am a self-proclaimed mechanic, rather a SUPER HARD CORE CAR GUY - I own a shop but no longer have any real hands on involvement, rather I diagnose problems and let others bust their knuckles, I do however take pride hands on when it comes to my supercharged z06, big turbo Audi S4, 4 rock crawler fully built jeeps, bike, etc - toys offer a level of reward unlike anything else. Keep in mind this failed boating diagnosis has been humbling for several reasons but primarily because my trusting wife has been supporting me in time and emotion along the way with no results. If you are still reading (you're crazy!), please offer suggestions. This post was only this long from the get-go to eliminate dozens of other posts where I'd have to clarify my process thus fad. I hope this will eventually not only lead to a result for me but also provide useful information for future readers.
