502 MPIs
02-23-2017, 08:32 AM
#1
Platinum Member
Platinum MemberThread Starter
iTrader: (2)
502 MPIs
Sorry but this will be long...
My "new to me" Formula 311 has a pair of Gen VI 502 MPI's. I bought the boat from a marina up in Maryland at a great discount because the engines were both toast in the opinion of the mechanic there. I know the boat's history pretty well, and have made friends with the guy that's owned the boat for the last 27 years so I was surprised and very disappointed to hear that there was something wrong with her (she was delivered running like a top).
Port engine... bad misfire. Checked compression and all were low (but within spec). They replaced a cracked sea strainer and raw water pump, and replaced the cap and rotor. Left the rest as is. Recommended cylinder head r&r.
Starboard engine... bad misfire. Checked compression and all were low (but within spec) with the exception of one that was 15 lbs higher. Changed out a cracked strainer, and threw plugs, cap and rotor, and fuel filter at it. Performed a leak down test and found 3 and 6 to have 95 and 80 percent leakage. Left it as is.
I made an offer, Formula countered, and I bought the boat. There was so much potential that I couldn't walk away. I have the work order for what was done, but then after speaking with the mechanic, I couldn't really trust what he was telling me since it contradicted the work order (I think he thought he was talking to someone that didn't know any better).
I get the boat home and start messing around. Since the port engine was the better of the two, I fired her up. Bad misfire!! Like a bad exhaust valve, though bringing up idle would remove it. Moved onto the starboard engine. Fired her up. Bad misfire but it as bad as the port engine. Also, idle surging and cutting off. A bump in the throttle would keep her running with little surge if any. Both engines sounded lazy. I shut her down and tried to restart, but batteries were low so I went on to cleaning her up (the marina did nothing to make her nice for me).
While thinking about it, I came to the conclusion that either a valve is severely burnt, or that there was an ignition problem. I get up in the boat and go to check the firing order.... the wires at the cap were numbered: 1,8,4,5,6,3,7,2. I was thinking... this can't be! I traced the wires and sure enough they were weird incorrectly... on both engines! I put power and water to the port engine, fired her up, and she was running like I'd expect from a good running BBC. Switch water paths over to the starboard engine... same thing but with a surging idle. Looks like I made out like a bandit especially considering what I paid for her (you guys would t believe me even with the Bill of Sale)!
Anyway... I know the above was long. At this point there are some assumptions:
1. The mechanic's test data cannot be relied upon at all.
2. Both engines run so smoothly (above idle the starboard engine shows no issues) and rev as you would expect that I don't think further testing on the block is needed.
3. I think we're really dealing with a EFI issue on the starboard engine.
4. A water test is needed to really be sure of performance.
My plan now is to clean the throttle bodies on both engines as well as the IAC on the starboard engine to see if the idle cleans up. I do not have a way of interfacing with the ECM, but I will by next week. Again, the engine runs too smoothly for me to suspect any issues as indicated by this guy's leakdown test, and his bumbling of the firing order issue ( as well as some other things) leave me with no confidence of this guy's abilities.
What do you guys think? Any tips or tricks to go with on the IAC or TPS front?
Thanks for reading!
-Tom
My "new to me" Formula 311 has a pair of Gen VI 502 MPI's. I bought the boat from a marina up in Maryland at a great discount because the engines were both toast in the opinion of the mechanic there. I know the boat's history pretty well, and have made friends with the guy that's owned the boat for the last 27 years so I was surprised and very disappointed to hear that there was something wrong with her (she was delivered running like a top).
Port engine... bad misfire. Checked compression and all were low (but within spec). They replaced a cracked sea strainer and raw water pump, and replaced the cap and rotor. Left the rest as is. Recommended cylinder head r&r.
Starboard engine... bad misfire. Checked compression and all were low (but within spec) with the exception of one that was 15 lbs higher. Changed out a cracked strainer, and threw plugs, cap and rotor, and fuel filter at it. Performed a leak down test and found 3 and 6 to have 95 and 80 percent leakage. Left it as is.
I made an offer, Formula countered, and I bought the boat. There was so much potential that I couldn't walk away. I have the work order for what was done, but then after speaking with the mechanic, I couldn't really trust what he was telling me since it contradicted the work order (I think he thought he was talking to someone that didn't know any better).
I get the boat home and start messing around. Since the port engine was the better of the two, I fired her up. Bad misfire!! Like a bad exhaust valve, though bringing up idle would remove it. Moved onto the starboard engine. Fired her up. Bad misfire but it as bad as the port engine. Also, idle surging and cutting off. A bump in the throttle would keep her running with little surge if any. Both engines sounded lazy. I shut her down and tried to restart, but batteries were low so I went on to cleaning her up (the marina did nothing to make her nice for me).
While thinking about it, I came to the conclusion that either a valve is severely burnt, or that there was an ignition problem. I get up in the boat and go to check the firing order.... the wires at the cap were numbered: 1,8,4,5,6,3,7,2. I was thinking... this can't be! I traced the wires and sure enough they were weird incorrectly... on both engines! I put power and water to the port engine, fired her up, and she was running like I'd expect from a good running BBC. Switch water paths over to the starboard engine... same thing but with a surging idle. Looks like I made out like a bandit especially considering what I paid for her (you guys would t believe me even with the Bill of Sale)!
Anyway... I know the above was long. At this point there are some assumptions:
1. The mechanic's test data cannot be relied upon at all.
2. Both engines run so smoothly (above idle the starboard engine shows no issues) and rev as you would expect that I don't think further testing on the block is needed.
3. I think we're really dealing with a EFI issue on the starboard engine.
4. A water test is needed to really be sure of performance.
My plan now is to clean the throttle bodies on both engines as well as the IAC on the starboard engine to see if the idle cleans up. I do not have a way of interfacing with the ECM, but I will by next week. Again, the engine runs too smoothly for me to suspect any issues as indicated by this guy's leakdown test, and his bumbling of the firing order issue ( as well as some other things) leave me with no confidence of this guy's abilities.
What do you guys think? Any tips or tricks to go with on the IAC or TPS front?
Thanks for reading!
-Tom
Last edited by TomZ; 02-23-2017 at 08:37 AM.
02-23-2017, 08:48 AM
#2
Platinum Member
Platinum Member
iTrader: (6)
Id get your scanner hooked up and see if it finds any code faults, then go from there, maybe send the injectors out for service, and Id keep that Dip Chit mechanic away from your boat...
02-23-2017, 09:10 AM
#3
Registered
iTrader: (1)
Sorry but this will be long...
My "new to me" Formula 311 has a pair of Gen VI 502 MPI's. I bought the boat from a marina up in Maryland at a great discount because the engines were both toast in the opinion of the mechanic there. I know the boat's history pretty well, and have made friends with the guy that's owned the boat for the last 27 years so I was surprised and very disappointed to hear that there was something wrong with her (she was delivered running like a top).
Port engine... bad misfire. Checked compression and all were low (but within spec). They replaced a cracked sea strainer and raw water pump, and replaced the cap and rotor. Left the rest as is. Recommended cylinder head r&r.
Starboard engine... bad misfire. Checked compression and all were low (but within spec) with the exception of one that was 15 lbs higher. Changed out a cracked strainer, and threw plugs, cap and rotor, and fuel filter at it. Performed a leak down test and found 3 and 6 to have 95 and 80 percent leakage. Left it as is.
I made an offer, Formula countered, and I bought the boat. There was so much potential that I couldn't walk away. I have the work order for what was done, but then after speaking with the mechanic, I couldn't really trust what he was telling me since it contradicted the work order (I think he thought he was talking to someone that didn't know any better).
I get the boat home and start messing around. Since the port engine was the better of the two, I fired her up. Bad misfire!! Like a bad exhaust valve, though bringing up idle would remove it. Moved onto the starboard engine. Fired her up. Bad misfire but it as bad as the port engine. Also, idle surging and cutting off. A bump in the throttle would keep her running with little surge if any. Both engines sounded lazy. I shut her down and tried to restart, but batteries were low so I went on to cleaning her up (the marina did nothing to make her nice for me).
While thinking about it, I came to the conclusion that either a valve is severely burnt, or that there was an ignition problem. I get up in the boat and go to check the firing order.... the wires at the cap were numbered: 1,8,4,5,6,3,7,2. I was thinking... this can't be! I traced the wires and sure enough they were weird incorrectly... on both engines! I put power and water to the port engine, fired her up, and she was running like I'd expect from a good running BBC. Switch water paths over to the starboard engine... same thing but with a surging idle. Looks like I made out like a bandit especially considering what I paid for her (you guys would t believe me even with the Bill of Sale)!
Anyway... I know the above was long. At this point there are some assumptions:
1. The mechanic's test data cannot be relied upon at all.
2. Both engines run so smoothly (above idle the starboard engine shows no issues) and rev as you would expect that I don't think further testing on the block is needed.
3. I think we're really dealing with a EFI issue on the starboard engine.
4. A water test is needed to really be sure of performance.
My plan now is to clean the throttle bodies on both engines as well as the IAC on the starboard engine to see if the idle cleans up. I do not have a way of interfacing with the ECM, but I will by next week. Again, the engine runs too smoothly for me to suspect any issues as indicated by this guy's leakdown test, and his bumbling of the firing order issue ( as well as some other things) leave me with no confidence of this guy's abilities.
What do you guys think? Any tips or tricks to go with on the IAC or TPS front?
Thanks for reading!
-Tom
My "new to me" Formula 311 has a pair of Gen VI 502 MPI's. I bought the boat from a marina up in Maryland at a great discount because the engines were both toast in the opinion of the mechanic there. I know the boat's history pretty well, and have made friends with the guy that's owned the boat for the last 27 years so I was surprised and very disappointed to hear that there was something wrong with her (she was delivered running like a top).
Port engine... bad misfire. Checked compression and all were low (but within spec). They replaced a cracked sea strainer and raw water pump, and replaced the cap and rotor. Left the rest as is. Recommended cylinder head r&r.
Starboard engine... bad misfire. Checked compression and all were low (but within spec) with the exception of one that was 15 lbs higher. Changed out a cracked strainer, and threw plugs, cap and rotor, and fuel filter at it. Performed a leak down test and found 3 and 6 to have 95 and 80 percent leakage. Left it as is.
I made an offer, Formula countered, and I bought the boat. There was so much potential that I couldn't walk away. I have the work order for what was done, but then after speaking with the mechanic, I couldn't really trust what he was telling me since it contradicted the work order (I think he thought he was talking to someone that didn't know any better).
I get the boat home and start messing around. Since the port engine was the better of the two, I fired her up. Bad misfire!! Like a bad exhaust valve, though bringing up idle would remove it. Moved onto the starboard engine. Fired her up. Bad misfire but it as bad as the port engine. Also, idle surging and cutting off. A bump in the throttle would keep her running with little surge if any. Both engines sounded lazy. I shut her down and tried to restart, but batteries were low so I went on to cleaning her up (the marina did nothing to make her nice for me).
While thinking about it, I came to the conclusion that either a valve is severely burnt, or that there was an ignition problem. I get up in the boat and go to check the firing order.... the wires at the cap were numbered: 1,8,4,5,6,3,7,2. I was thinking... this can't be! I traced the wires and sure enough they were weird incorrectly... on both engines! I put power and water to the port engine, fired her up, and she was running like I'd expect from a good running BBC. Switch water paths over to the starboard engine... same thing but with a surging idle. Looks like I made out like a bandit especially considering what I paid for her (you guys would t believe me even with the Bill of Sale)!
Anyway... I know the above was long. At this point there are some assumptions:
1. The mechanic's test data cannot be relied upon at all.
2. Both engines run so smoothly (above idle the starboard engine shows no issues) and rev as you would expect that I don't think further testing on the block is needed.
3. I think we're really dealing with a EFI issue on the starboard engine.
4. A water test is needed to really be sure of performance.
My plan now is to clean the throttle bodies on both engines as well as the IAC on the starboard engine to see if the idle cleans up. I do not have a way of interfacing with the ECM, but I will by next week. Again, the engine runs too smoothly for me to suspect any issues as indicated by this guy's leakdown test, and his bumbling of the firing order issue ( as well as some other things) leave me with no confidence of this guy's abilities.
What do you guys think? Any tips or tricks to go with on the IAC or TPS front?
Thanks for reading!
-Tom
02-23-2017, 09:42 AM
#5
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Platinum MemberThread Starter
iTrader: (2)
I cannot give specifics regarding the previous owner, but I believe all of this transpired after everything was done with a new boat purchase. At the point where I got involved, I believe Formula owned or was the agent for the boat.
02-23-2017, 09:55 AM
#9
02-23-2017, 10:01 AM
#10
Registered
iTrader: (2)
I had to uncobble a reverse rotation 427 ford at a marina once . I think in their final act of despiration, they just started guessing firing orders, once they figurred out where #1 was .
It ran , and didnt backfire , but would only turn 3500 or so rpm. They told him same thing . Motor was toast
It ran , and didnt backfire , but would only turn 3500 or so rpm. They told him same thing . Motor was toast
