MerCruiser 3.0 L coldstart problems

[Cold whack]

I have a 1989 MerCruiser 3.0 L alpha-1 I got this boat recently from a guy who let it sit for about three years .I have done a bit of maintenance myself,oil change ,fuel filter ,spark plugs ,waterpump impeller . I have also had the carburetor rebuilt by a friend and I'm wondering if the job was done right. It still seems to have problems starting when it has been sitting for three or four days, I have to pump the throttle three or four times in order for the motor to fire ,Is this normal or do I still have a carb issue or could it be fuel pump or something else. thanks guys

 

[jimbo_jwc]

Re: MerCruiser 3.0 L coldstart problems

Your learning curve is close to ending . You still need to check/clean antisiphon valve and probable replace fuel pump , check choke butterfly open adj . and sometimes you still might have to use the accelerator pump to start faster .

 

[fat fanny]

Re: MerCruiser 3.0 L coldstart problems

Carb re-builds have a 50/50 shot at success also did you clean out the bowl on the fuel pump and replace it's (most likely) stone filter? And are you getting 2 streams of fuel into the air horn when manualy activating the accelerator? Also as said proper adjustment of the choke is nessasary after a re-build for proper operation. Good luck and post back!

 

[Cold whack]

Re: MerCruiser 3.0 L coldstart problems

Hey guys thanks for replying so quickly I have replaced stone filter I am not quite sure how to adjust butterfly any tips would be great

 

[Silvertip]

Re: MerCruiser 3.0 L coldstart problems

Stone cold engine. Remove flame arrestor, check choke plate position. It should be closed but when you use your finger on the back side to force it open and release it it should not slam shut. Loosen the adjustment screws on the disk and rotate it so the choke beings to open. Then rotate it back until the choke plate just closes. Start the engine and as it warms up the choke should gradually open and when fully warmed up should stand perfectly vertical in the bore. DO NOT DO THIS ON A WARM ENGINE. Chokes are needed for COLD start and are adjusted accordingly.

 

[Cold whack]

Re: MerCruiser 3.0 L coldstart problems

Oh and sorry about my inexperience but the anti-siphon valve is that connected to the fuel pump or the carburetor

 

[Don S]

Re: MerCruiser 3.0 L coldstart problems

Oh and sorry about my inexperience but the anti-siphon valve is that connected to the fuel pump or the carburetor

Neither, it's on the gas tank. But the anti syphon, nor your fuel pump is the problem. If they were at fault it not only would be hard to start, it wouldn't keep running or run fine at higher rpm.

it's also normal to pump a carbed engine 1 or 2 times to start, and after setting for a few weeks may take an extra pump.

Here is a copy and paste from an owners manual on how to start a carbed engine. Then it should start easily again.


Starting And Stopping The Engine

NOTE: Only perform those functions applicable to your power package.
1. Check all items listed in Operation Chart.
2. Place the remote control handle in NEUTRAL.

CAUTION
Overheating from insufficient cooling water will cause engine and drive system
damage. Ensure that there is sufficient water always available at water inlet holes
during operation.

WARNING
Explosive gasoline fumes collect in the engine compartment. Avoid injury or
property damage, operate the bilge blower for at least five minutes prior to starting
the engine. If the boat is not equipped with a bilge blower, open the engine hatch
and leave it open while starting the engine.

3. Push THROTTLE ONLY button and position throttle setting as follows:
a. COLD ENGINE - Move control/throttle lever to full throttle, then return to about 1/4
throttle. In extreme cold it may be necessary to pump lever more than once.
b. WARM ENGINE - Move control/throttle lever to 1/4 throttle position.
c. FLOODED ENGINE - Move control/throttle lever to full throttle. Be prepared to
decrease engine speed to 1000-1500 RPM as soon as engine starts.
IMPORTANT: Do not operate starter motor continuously for more than 30 seconds.
4. Turn ignition key to START. Release key when engine starts and allow switch to return
to ON position.

5. Operate engine for 1 or 2 minutes at fast IDLE (1000-1500 rpm) or until engine temperature
reaches 140-160 degrees F (60-71 degrees C).
6. Inspect the power package for fuel, oil, water and exhaust leaks.
7. To shift into gear, move control handle with a firm, quick motion forward to shift to FORWARD
gear, or backward to shift to REVERSE. After shifting drive unit, advance throttle
to desired setting.
8. Move the remote control handle to NEUTRAL/IDLE and allow the engine to slow to IDLE
speed. If engine has been operated at high speed for a long period of time, allow the
engine to cool at IDLE speed for 3 to 5 minutes.
9. Turn ignition key to the OFF position.

 

[fishrdan]

Re: MerCruiser 3.0 L coldstart problems

Oh and sorry about my inexperience but the anti-siphon valve is that connected to the fuel pump or the carburetor

Fuel tank...

On a cold engine, you need to pump the throttle at least once to release the choke plate. Then pump it a couple times more to prime the engine, to give it a rich charge to start with. Once the engine is started, bump the idle to 1000-1200RPM for a couple of minutes to warm it up.

 

[thumpar]

Re: MerCruiser 3.0 L coldstart problems

Don's instructions work for me every time. If that doesn't work for you check the choke and if still no go then I would suspect the rebuild or something else.