I have a 96 3.0 and have been having some problems with it seeming to miss when idle or going through a no wake zone. It runs perfect when cruising or hammer down. Starts immediately, idles good for a couple minutes then seems like a misfire happens. I rev it up and it cleans out. I have changed plugs, primer bulb and drained water sep. Anything else I should check? Please help.
Not really enough information to form an opinion from......
I would recommend you look through the following post, and ensure that ALL recommended items were addressed (preferably ALL at the SAME TIME):
http://www.bbcboards.net/zerot...first
Use ONLY CHAMPION QL77CC Spark plugs.
Verify TPS Voltage at idle. This is CRITICAL to proper engine performance.
Also, verify fuel pressure AT IDLE, under acceleration, and 15 seconds/ 30 seconds after keydown.
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
Checked fuel line and looks good. Motor did the same thing today. Got to lake it fired up instantly and ran fine for about 5 min. Until it warmed up then it felt like a miss. If I give it some gas it goes away until I let it idle again. Again it runs perfect when above I would say 1500 rpm. I will check pressure later. Thanks
JVA,check for power output at idle speed,if a cylinder is low and still has good spark,suspect a chipped reed,Chris
Had a similar situation on my 175 EFI. I found that one of the drains in the back of the outer plastic case had popped up out of its hole allowing water to come in when it came down off plane thus wetting the plug wires, coil etc. Then, it would clear out when they dried off. Mine had little rubber drains that looked like a kazoo that only allowed water to run out, but one had popped up out of its hole and was laying in the bottom of the housing.
Fuel pressure stays around 35 to 37 but leaks down to 30 after shut down pretty quick. Can Anyone tell me what the tps voltage is suppose to be? I'm getting some crazy numbers. I have 3 wires black, blue/yellow and blue/red.
TPS voltage (at idle) should be .95 VDC (=/- .05 VDC).
Preferably, aim for .95-.98 VDC range.
Does your fuel pressure hold CONSISTENTLY at 30 psi after keydown (or does it continue to leak down)?
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
It stays at 30 for a while. On my tps it seems to be backwards. Idle 3.67 wot 1.73. Any suggestions?
read the voltage using the red and white wires, not the black
Thats if you are using the test harness.
No red or white wires. Only Blue/red, Black, Blue/yellow.
O.K real crazy got me straightened out on the tps. Idle was 1.09 wot was 3.96. I reset to .95. Idle. Could that little bit off be causing my problem? If not can anyone suggest what I can check next?
I would recommend that you ensure you have a clean set of plugs installed, and then run it to see how it does.
If you're still having idle problems after this, other items that should be checked include:
-Sync-n-Link Adjustments
-Bleed Lines & Check Valves
-Injectors (Clean/Flow Test)
-Reeds
Be sure to report back on your results.
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
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