Dennis Moore, John B, and the HP500 EFI
09-22-2003, 10:04 AM
#12
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Re: I am glad someone spoke up!
Originally posted by KAAMA
Hopefully the "Technical Q & A" section won't become slanted to the point where only a "select few" will be able to answer questions----of course I could be wrong, but that is what I suspect is slowly happening and that we're sadly heading in that direction, and if we voice our concern about it we will either be told if we don't like it we can leave or get booted off. I welcome all opinions---not exclusively just Dennis Moore's or anyone elses opinion!----Although I do respect his input on many subjects. I bought his book! So I am glad you guys brought this up because I wanted to respond to this thread as to what I see happening as well! We just have to keep our cool about it.
Hopefully the "Technical Q & A" section won't become slanted to the point where only a "select few" will be able to answer questions----of course I could be wrong, but that is what I suspect is slowly happening and that we're sadly heading in that direction, and if we voice our concern about it we will either be told if we don't like it we can leave or get booted off. I welcome all opinions---not exclusively just Dennis Moore's or anyone elses opinion!----Although I do respect his input on many subjects. I bought his book! So I am glad you guys brought this up because I wanted to respond to this thread as to what I see happening as well! We just have to keep our cool about it.
09-22-2003, 10:11 AM
#13
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According to my Mercury 500EFI service manuel, the rev limiters are set @5400.
It also shows that the motors are 509's, instead of 502". They may have just rounded up the bore from 4.47 to 4.50 though.....
I believe (might be wrong) Mercury cuts power to the electric fuel pumps to accomplish the limit.
It also shows that the motors are 509's, instead of 502". They may have just rounded up the bore from 4.47 to 4.50 though.....
I believe (might be wrong) Mercury cuts power to the electric fuel pumps to accomplish the limit.
09-22-2003, 10:32 AM
#14
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jdnca1,
The high rev protection is through the injectors and not the pump.
By the way, my service manual does not vary from a 4.47" bore (or 4.468") - where does yours go to 4.50"? Also, where does you manual have the limiter specifications? What service manual do you have?
Thanks
The high rev protection is through the injectors and not the pump.
By the way, my service manual does not vary from a 4.47" bore (or 4.468") - where does yours go to 4.50"? Also, where does you manual have the limiter specifications? What service manual do you have?
Thanks
09-22-2003, 10:40 AM
#15
mcollinstn, Good post! makes sense, good explanation! I must have been thinking carburetors---Da
My experience with the 500 efi rev limiter was -- when rpm reached 5400+-, certain injectors shut off (I believe this is a batch fire system) and they would not fire again until the rpm was below 5250. At this point you have lost speed and the motor would again try to accelerate back to the rev limit. This could appear that the limit was 5250 if you looked at the tack. This information is from Mercury.
I would still be interested in the black spark plug issue. I just spent an hour cleaning my transom again. Do the aftermarket supercharger systems (the programming) also cause sooty transoms?
I'm glad we are back into technical talk!
My experience with the 500 efi rev limiter was -- when rpm reached 5400+-, certain injectors shut off (I believe this is a batch fire system) and they would not fire again until the rpm was below 5250. At this point you have lost speed and the motor would again try to accelerate back to the rev limit. This could appear that the limit was 5250 if you looked at the tack. This information is from Mercury.
I would still be interested in the black spark plug issue. I just spent an hour cleaning my transom again. Do the aftermarket supercharger systems (the programming) also cause sooty transoms?
I'm glad we are back into technical talk!
09-22-2003, 01:30 PM
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Well, I try to run mine slightly rich too to keep the pistons a little cooler and to prevent the holley secondary transition from going lean, but I would think the computerized injected engines from Merc would be able to be controlled a little better than "black transoms".
09-22-2003, 02:10 PM
#20
Octane
These plugs were run with 87 octane. The first year or so of ownership I ran 89 to 93. Sometimes because of availability, I ran 93. Sooting seemed worse with higher octane.
See picture of plugs: http://www.offshoreonly.com/forums/s...threadid=59276 post #9
If the throttle position sensor signals the A/F ratio for mid-range, maybe mine are set wrong. Is this possible?
Troutly, I can understand why the would want to be rich at WOT. But they look somewhat lean, see the above post dyno test. I think they are richer in the mid range than WOT. I would like to to see some exhaust temperature data in the 3500 rpm range at 1/3 throttle and 200 hp output. I would bet the exhaust temps are under 1100 to 1200.
Warrantee claims end after one year. I don't think motors with plugs that look like mine are going to make it to 500 hours.
See picture of plugs: http://www.offshoreonly.com/forums/s...threadid=59276 post #9
If the throttle position sensor signals the A/F ratio for mid-range, maybe mine are set wrong. Is this possible?
Troutly, I can understand why the would want to be rich at WOT. But they look somewhat lean, see the above post dyno test. I think they are richer in the mid range than WOT. I would like to to see some exhaust temperature data in the 3500 rpm range at 1/3 throttle and 200 hp output. I would bet the exhaust temps are under 1100 to 1200.
Warrantee claims end after one year. I don't think motors with plugs that look like mine are going to make it to 500 hours.
