What causes hard starting and rough idle on a Mercury?

Faulty Air Temperature Sensor: Will cause hard starting and rough idle. Air temp sensor should be checked with an Ohm Meter with a Cold Start Ignition Test. *ACU and PCU only. Incorrect fuel pressure: Can be caused by a bad fuel pressure regulator, or restricted return. On Laser EFI motors, look under the Fuel Pressure Regulator.

What are the symptoms of a bad idle control valve?

$0.00 1 Irregular idle speed One of the most common symptoms commonly associated with a problematic idle air control valve is irregular idle speed. 2 Check Engine Light comes on Another symptom of a potential issue with the idle control valve is an illuminated Check Engine Light. 3 Engine stalling

Why do I get a rough idle when I Turn Off the engine?

In direct injection engines, the fuel injector delivers fuel right into the cylinder; so the valves never get fuel spray. After shutdown, crankcase vapors rise to the top of the engine and settle on the intake valves; where they condense and harden. The result is, carbon buildup that can cause, a rough engine idle.

Why does the Check Engine light come on when the engine is idle?

The check engine light in your vehicle is designed to turn on if the Engine Control Unit (ECU) identifies an issues with how the engine is running. Look at your dashboard; if the check engine light is on in conjunction with idle issues, it may be because the idle control valve is malfunctioning.

What happens when the idle air control valve ( IAC ) fails?

When the idle air control valve (IAC) fails it can cause all sorts of issues; and in some cases may even render it undrivable. Usually, a bad or failing idle air control valve (IAC); will produce a few symptoms that can alert the driver of a potential issue:

What should I do if my outboard engine is idling?

If your outboard has fuel injection instead of a carburetor, try cleaning the idle air control (IAC) valve. This valve regulates airflow into the engine, so make sure it isn’t clogged with dirt and air can pass through it freely. If it is clogged, clean or replace the IAC valve. Check the Fuel and Air Filters

When is a bad throttle position sensor a warning sign?

Engine won’t idle smoothly, idles too slowly, or stalls If you start to experience engine misfires, stalling, or rough idling when the car is stopped, it can also be a warning sign of a failing TPS. You don’t want to wait to get this checked out!

Why does my car stall at low rpm?

The will likely force your computer to stall the engine and only allow it to run at low RPMs, which means the car will only move at slow speeds. This is a safety feature enforced by the computer so that your engine doesn’t get too damaged.

What causes idle surges on a car ECM?

Idle surging can be caused due to other issues in the car, but if it happens in conjunction with other throttle position sensor symptoms, the culprit is often the TPS. At idle, the ECM will not get the correct information and the throttle will variate randomly causing idle surges.

Why does my mercury 115 EFI not start?

My mercury 115 EFI four stroke develops an engine miss at around 5000 rpm. The rpm drops approx 200 to 400 rpm. This miss comes and goes. It appears … cold Engine cranks quickly but does not start. will start if using starting fluid. carbs rebuilt. new fuel,new squeeze ball, electric choke. new plugs …

Which is the best forum for Mercury outboard problems?

This is the best Mercury Outboard Forum on the internet, it’s yours! If you own a Mercury Outboard. Are you looking for good advice about your Mercury outboard engine problems and issues.

Why does my outboard engine sputter at full throttle?

by Dan Harkins If your outboard engine is sputtering at any speed, idle or full throttle, it could be the result of several common malfunctions. You may need to make a few timing adjustments or replace a spark plug, or you may need serious mechanical inquiry.

Where did my Mercury outboard motor come from?

I bought this motor as a clearance in 2009 in Delaware USA ( new in crate) I then moved to Australia, and the motor stayed in the crate until 2 days ago…. … When I turn the key I get the beep, but there is a 2-3 hesitation before the motor starts to turn over. After a couple tries, the motor starts and runs …

Why does my mercury stall at low speed?

The gas/oil was also 1.5 months old (getting there but should not<br>be stale yet). The motor took a while to start which I expected. When<br>it did start it would stall after idling for about 30-40 seconds. If I<br>ran it a med-high throttle it would run fine, but at low speed it<br>would stall.

What causes a Mercury 9.9 hp two stroke to stall?

A friend of mine had this same problem. It turned out to be a loose, or pinched, o-ring inside the coupler. $5 later after a stop at Walmart and all was well. Try squeezing the bulb while the engine is off. It any gas leaks from the coupler, you have the same problem. point! >Check the fuel line coupler where it connects to the engine. A friend of

What causes a MerCruiser 4.3L CARB to stall?

Problem started easter weekend (last week) out on the water 2. Have trouble starting, but engine seems to run fine when under throttle (ran great on the water) 3. When in neutral/idle, will stall out after 10 seconds or so. 4. When it does idle, its very weak…around 400 rpms (should be 650)

What to do if your Mercury Mountaineer starts stall idle?

I recommend a BG Induction service if you have never had this done and your vehilce is over 65,000 miles. Mercury Mountaineer 2004, AWD, V8. Bought this used with 40k miles on it. The engine dies (dead) when using the cruise control. control, several minutes pass by and suddenly the engine is dead.

What kind of problem does Mercury Mountaineer have?

Mercury Mountaineer 2004, AWD, V8. Bought this used with 40k miles on it. The engine dies (dead) when using the cruise control. control, several minutes pass by and suddenly the engine is dead. Most of the warning lights in the instrument cluster come on.

When does a Mercury outboard run rough and stalls?

Mercury outboard idles rough and/or stalls refers to when a Mercury outboard runs in an irregular or uneven manner while in neutral or out of gear.

Why does my Chevy Cobalt have rough idle?

An internal combustion engine needs air, fuel, and spark in order to achieve ignition. When one or more of these variables is off it can lead to a rough idling condition. Most of the time the culprit is going to be the ignition system, although there are a myriad of other causes.

What causes rough idle on an Audi A4?

Ignition Coil Packs – Nearly all model years and engines use coil packs. These packs are fired by the engines computer at exactly the right time to provide the optimal ignition timing. If a coil pack goes bad, it’ll cause a misfire and rough idle condition.

What causes a car to have a rough idle?

The engine can run too rich or too lean. A too-rich mixture will result in poor fuel economy. A too-lean mixture will cause a rough idle. Solution: Since the oxygen sensor is part of the emissions system, its failure will usually trip a trouble code in the engine computer.

What to do if your fuel injector is rough idle?

Another option is to try to clean your fuel injectors with a fuel system additive like Techron, or something similar. While an additive may or may not have much effect on your rough idle problem, you can consider this as a last-ditch effort before visiting your mechanic. Follow the directions on the product’s label.

When did the Mercury 4 stroke fuel problems happen?

Last edited by BobG on Fri Sep 14, 2012 8:18 pm, edited 1 time in total. I’m not a liberal, but I play one on this site. Just because a part is under its 5th revision that does not tell you a damned thing.

Why does my car idle at a higher RPM?

This also creates a vacuum within the intake manifold. These hoses can wear out over time and a leak may develop. If too much air gets mixed in with the fuel, it will cause your engine to misfire. This will result in a rough idle, usually at a higher RPM.

What kind of engine does a Mercury outboard have?

FIXED my rough Idle + stall problem 60HP EFI Mercury Outboard 2005 Four stroke engine! – YouTube

What to do if your car engine has rough idle?

If you own an old car and are experiencing rough idling, it is a good idea to clean the carburetor and check the hoses for damage or dirt buildup. Rough idling is a serious issue and should not be ignored for a long time. If the problem persists and is not fixed, it can lead to engine failure as well.

Why does my 90 elpto stall at idle?

My 90 ELPTO is quite rough at idle, even stalling occasionally. I’ve been told rough idle is the nature of the beast and is common for all Mercury 2-strokes as they are optimized for riding. Fair enough but what’s the root cause of rough idle? (assuming all components work as designed)

What causes rough idle on an iboats boat?

Yes, uneven compression will cause rough idle as well as MANY OTHER THINGS. Check fuel quality, compression and plug appearance first. Then move on to spark quality, idle timing and carb adjustments. You have to start somewhere….

Which is better 2 stroke idle or 4 stroke idle?

Rough idle is a subjective statement. If all is normal, 2-stroke idle is acceptable. Sometimes near as good as a 4-stroke. Many things can affect idle quality. Probably too many to mention. The one that we fear the most is uneven compression. Once all three are verified the motor should purr.

What are the symptoms of a cracked engine block?

5 Symptoms of a Cracked Engine Block 1 Oil & Antifreeze Mixture. Engine oil and antifreeze fluid can mix together if there is a serious crack in the engine block. 2 Engine Smoke. A huge symptom of a cracked block is smoke coming out of the engine. 3 Seeing a Crack in the Block. 4 Engine Overheating. 5 Low Compression. …

How to diagnose a faulty fuel pump failure?

In this video we go over the basic steps of diagnosing a faulty fuel pump. So if your vehicle isn’t starting and you suspect a fuel pump problem, here are some steps to follow to confirm your suspicions. Another ‘quick’ test is to bang on the fuel tank and then try and start the engine.

Can a cracked engine block mix with antifreeze?

Here are five common signs you can expect from a cracked engine block. Engine oil and antifreeze fluid can mix together if there is a serious crack in the engine block. The antifreeze fluid will be able to find its way through the crack and then circulate with the oil.

What are the symptoms of a failing body control module?

5 Common Symptoms of a Failing Body Control Module (BCM) You are here: The Body Control Module (BCM) could be considered a central organizational module for your vehicle. It streamlines the manufacturing and troubleshooting aspects of electronic modules by housing the modules into one, central unit instead of each function having its own device.

How to troubleshoot a Mercury outboard engine?

Check for a dirty or old spark plug, improper carburetor adjustments, or broken or faulty ignition wires. Air vent in fuel cap not open. Faulty emergency kill switch. Some engines — not the pull-start kind — have a battery that starts it.

What to do if your mercury light shuts off?

Check the compatibility of your mercury vapor bulb and its ballast if the light shuts off before it is fully warmed up. Make sure the wattage ratings of the bulb and ballast match.

How to troubleshoot mercury vapor lights you Hunker?

How to Troubleshoot Mercury Vapor Lights Step 1. Make sure the light fixture is plugged in and the circuit breaker switch is on. Replace any blown fuses at the… Step 2. Replace the light bulb if it flickers, dims or changes colors drastically. Be sure to install the light… Step 3. Check the …

Check the compatibility of your mercury vapor bulb and its ballast if the light shuts off before it is fully warmed up. Make sure the wattage ratings of the bulb and ballast match.

How long to cool down mercury vapor light?

Allow the bulb to cool down for 10 to 15 minutes if you are trying to turn the light back on after a recent use. Check the compatibility of your mercury vapor bulb and its ballast if the light shuts off before it is fully warmed up. Make sure the wattage ratings of the bulb and ballast match.

How does a MerCruiser engine work at idle?

When I start the engine from cold, I allow the engine to warm up at idle. This goes smoothly everytime. When I rev up the engine, either in neutral or under load, the engine works fine.

Why does my MerCruiser not surge when cold?

Part two of pulling of the coolant sensor is the ECM thinks the engine is cold so in-turn the RPM will be higher….Closer to 700 RPM and the desired idle will (should) be set higher as well which could be another reason the engine won’t surge when cold because the sensor values are all higher and the ECM is compensating for those readings.

This is the best Mercury Outboard Forum on the internet, it’s yours! If you own a Mercury Outboard. Are you looking for good advice about your Mercury outboard engine problems and issues.

What to do if your outboard motor won’t idle?

An outboard motor that won’t idle properly can be a real headache, especially when mooring with an engine that stalls every time you bump it into neutral. If playback doesn’t begin shortly, try restarting your device.

What to do if your fuel tank is not working?

A trickle flow is not good enough. If flow from the tank is poor – drain the tank into a clean bucket. Look inside the empty tank for debris and also check the line to the filter for debris. Flush out as necessary. Good Luck, and let us know what you find out.

What are the signs of a faulty fuel pump?

Faulty fuel pumps There can be a number of tell-tale signs that a fuel pump may be failing. Some of the obvious symptoms include a loud electrical clicking or whining noise when the engine is running even at idle.

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