hey guys im looking to find out what the fuel pressure spec is on my 98 225. it dosent do me much good to know what fuel pres i have if i dont know what it should be
hey guys im looking to find out what the fuel pressure spec is on my 98 225. it dosent do me much good to know what fuel pres i have if i dont know what it should be
NORMALLY, 34-46 psi range.
However.... it's much better if you determine what your pressure IS ACTUALLY:
-At idle
-Under acceleration (in the water)
-15 seconds after engine shutdown
-30 seconds after engine shutdown
Information from the above may lead to a more accurate diagnosis of problems (as apposed to you just saying "yeah... I've got good fuel pressure").
Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
Still consider myself a "Marine Apprentice" after 48 years (learn something new every day).
Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor
i will bring my fuel pressure gauge home from work and test it in the drive way but to take it out and run it tonight just isn't going to happen i will at some point however. should i c an increase in pressure as intake vacuum drops ?
Correct... there should be about 2-3 psi increase in fuel pressure when vaccum drops (you can also disconnect the vaccum line from the pressure regulator- accomplishing essentially the same thing).
Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
Still consider myself a "Marine Apprentice" after 48 years (learn something new every day).
Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor
good it dose not sound like the fuel system is much different than what i work on. (i work on cars for a living. and actually im on my computer acting like im looking up service info now while im talking to u lol but i guess my next ? is that the fuel pressure should stay in the fuel system and not leak back to the tank or out of a leeking injector thats the reason for the pres after 15 and 30 sec ?
sure wish they used OBD ll on mercs then i could work on it with my scan tool
Correct... you should see no substanial loss of pressure over 30 second period (if there is, there is a leak in the circuit SOMEWHERE).
Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
Still consider myself a "Marine Apprentice" after 48 years (learn something new every day).
Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor
cool thanks i will get back to you with the outcome of my tests
ok the numbers just in at idle 35psi when intake vacuum drops either by hiting the gas or taking the vacume line off the fpr the pressure is 39-40 after shut down the pressure is 31 after 15 sec and after 30sec it is 30 thats seems to be normal operation however i still have no power on take off i also noticed while testing it also has ngk plugs and i will be changing them as soon as i can get my hands on a set of ql77cc's but i dont have any cylinder miss fires so im thinking that isnt going to help the situation
I'd back up to the same basics you use in Automotive trade:
-Compression
-Spark
-Fuel (Quality, Pressure, Delivery)
You can read through the following post... recommend that ALL recommended items be done at the SAME TIME:
http://www.bbcboards.net/zerot...first
Also, verify that you have manifold vaccum present at the MAP sensor hose (critical).
Also wise to check the TPS voltage at idle, WOT (and of course, in between to check for any "glitches").
DEFINITELY get the correct plugs in it. You'd be amazed at the wide array of performance problems an "incorrect" spark plug can cause.
Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
Still consider myself a "Marine Apprentice" after 48 years (learn something new every day).
Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor
why dont u sell me some plugs. i cant find any around here. i checked tps voltage last year and you said it was ok i played with the map sensor last night and it has vacuum im not sure what kind of numbers are coming out of it but i dont know what wires are what i would assume that there are 3 one 5 volt ref ground and a signal back to the ecm but thats just how they work in my world. also does this engine have any way of metering what coming out of the motor like an o2 sensor or somthing ?
ps on the tps i put my snapon vantage (scope) on it and watched it from high to low and back no glitches in the wave form pattern
Your understanding of the Map sensor is correct... simple, 3-wire 5V sensor.
No O2 sensors... no mean of monitoring or adjusting for airflow changes. These engines are based on a "Speed-Density" theory (unlike the Mass-Airflow type you're accustomed to).
Sherm @ Sherm's Marine (or I) would be more than happy to assist you with Spark Plugs or other parts you may need.
Email or Phone are the BEST means of contacting the Parts Department(s).
Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
Still consider myself a "Marine Apprentice" after 48 years (learn something new every day).
Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor
i talked to my parts guy and he said champ came out with a new for that ql77cc said to be the same plug should i just try harder to find the ql?
<table width="90%" cellspacing=0 cellpadding=0 align=center><tr><td>Quote, originally posted by tommysorethumb »</td></tr><tr><td class="quote">i talked to my parts guy and he said champ came out with a new for that ql77cc said to be the same plug should i just try harder to find the ql?</td></tr></table>
Incorrect. Don't know what he's trying to sell you, but that QL77CC was specifically designed for Mercury's 3L EFI engines (and is the ONLY recommended plug for these models).
Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
Still consider myself a "Marine Apprentice" after 48 years (learn something new every day).
Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor
ok ill have to get them from u soon just cant call your place now i should be working while im here ..........
anyhow ausming that the plugs dont fix it what would be the next step ?
<table width="90%" cellspacing=0 cellpadding=0 align=center><tr><td>Quote, originally posted by tommysorethumb »</td></tr><tr><td class="quote">anyhow ausming that the plugs dont fix it what would be the next step ?</td></tr></table>
If you can, please provide your engine's serial number, and a specific statement of the symptoms you're experiencing.
Read back through this topic several times.... but am not really able to ascertain exactly what you're attempting to correct (perhaps I just missed it)?
Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
Still consider myself a "Marine Apprentice" after 48 years (learn something new every day).
Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor
i dont not have the numbers now but i will get them the symptoms are no power at low rpm like take off and puting on the trailer its not the prop i did some testing there i actually have to small a prop on it now its a 26 small hub trophy and that should put my boat in the bed of my truck when trying to go up the trailer and it will not even push the boat all the way up only about 3/4 the way when i put the prop that runs good on the boat (27 tempest plus ) i will plane but its really not easy with 2 ppl and that is with the pvs plugs removed once it gets over the plane stage it runns like hell at wot im turning that 27 tempest at 5800 and that is a bit much but with out fixing the problem a 28 would never break plane i have done all the things you said to check above fuel line tps map fuel pres and quality all pass the only thing i havent done is take the power head off and check the tuner
sorry about typos im at work and trying to hurry up and type
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