Starting when hot

[wtg2320]

I have had some issues with my 3.0 Mercruiser starting after driving it for a while. It will turn over fine, but will not start for about 5 minutes. I am new to boating so I am not sure if I am properly starting it right when warm. Should I leave the throttle in neutral or should I give it half or full throttle? I brought it to a marina and they ran it on the muffs and they said they could not get it to act up. They also said that the plugs wires and distributer cap needed to be replaced, so I did that. I am taking it back on the water this weekend to see if that helps. My main question once again is how would you suggest to start when warm? I had tried different things but none worked. I just want to make sure I am not adding human error into the equation this weekend while I am trying to see if it starts better now. Thanks.

 

[Bondo]

Ayuh,..... Normally, with a motor in good tune, just the touch of the key, should restart the motor,.....

If ya gotta go to neutral, 'n advance the throttle to restart, that would suggest a carb problem,....
If ya gotta pump the throttle to restart it, the carb is for Sure a problem,.....

'n of course, there's varyin' degrees of the motor bein' outa tune, 'n the effort it takes to restart it, sorta determines what needs tunin', 'n how badly it needs it,.....

 

[Scott Danforth]

My main question once again is how would you suggest to start when warm?
.

I would go thru the fuel system and fix the issues.

 

[Mercruisermike85]

Most likely the carb needs to be cleaned. I just had the same type of problem and just picked my boat up from the mechanic today, took out for an hour spin after he rebuild and cleaned my carb and it’s like a brand new boat all over again!

 

[JimS123]

When my 3.0 is cold I pump the throttle twice, advance it slightly and it fires up in a few seconds. Then, I back off the throttle to attain about 1000 rpm until the choke cuts out. Then, I back off the throttle to idle and it runs smooth and I shift into gear.

When Its hot, I do advance the throttle slightly in neutral but don't do the pump. It usually starts right up, so then I reduce the throttle back to the idle range.

If I don't advance the throttle at start it runs a bit rough. Nevertheless, depending upon how hot or cold it is, or how long it as been off, will determine how many seconds it takes to run smooth.

Is the carb dirty? I dunno. But its been acting this way since it was brand new. My performance curves and fuel economy would indicate no changes or problems.

 

[Mercruisermike85]

What year engine with what type of carb? TKS,electric chock or bi metal choke? It sounds like the idle jets could be gooched with gunk

 

[wtg2320]

It's an 88 mercruiser. Not sure what type of carb. How would I fix the idle jets if that is the issue

 

[Bondo]

It's an 88 mercruiser. Not sure what type of carb. How would I fix the idle jets if that is the issue

Ayuh,.... It's called Rebuild the Carb,....

 

[QBhoy]

I’d say it’s likely your auto choke is bad. Either fix it or bypass it by locking it off. Something I did to all my carb engines.

 

[wtg2320]

Just a quick update. The boat ran fine, but when it got hot, I had to fully throttle and then it would crank 5 or 6 times before it would start. After that, it ran fine again, it seems that replacing the plugs and cap really didn't fix much. Do you think making sure all the adjustments to the carb are set correctly accoriding to the manual would help fix this or is it more? I am not a mechanic by any means but after looking at the manual it doesn't seem to difficult.

 

[wtg2320]

after I disconnect the throttle cable barrel and make the adjustments to the idle speed adjustment screw and the idle mixture needle, would I then turn the barrel until it fits perfectly and then put it back on or would I leave the barrel where it is at?

 

[Bondo]

after I disconnect the throttle cable barrel and make the adjustments to the idle speed adjustment screw and the idle mixture needle, would I then turn the barrel until it fits perfectly and then put it back on or would I leave the barrel where it is at?

Ayuh,...... 1st off, I believe the carb needs to be Rebuilt, not just havin' it's screws turned, a full-on professional type carb rebuild,....
but anyways,....

To answer this quote,..... Nope,.....

The cable should be slightly pushin' against the idle adjustment screw,....
There has to be tension against the screw, to account for any slack in the cable,.....

 

[wtg2320]

Thanks for the advice, it has been rebuilt before u bought it can it be rebuilt more than once?

 

[SkiGuy1980]

Yes, carb can be rebuilt again and then you can tune the fuel flow to maximize performance.

Just a side note - I had a 4.3 that was difficult to start. I had the carb rebuilt and that helped... but even after I replaced plugs and wires I would still occasionally have issues. Finally discovered the cause for the inconsistent performance when the gear on the bottom of the distributor sheared off when we were miles from the dock (didn't think to pull that and make sure it wasn't worn). Looking back I think a good engine tech could have chased that one down and saved me a tow.

 

[wtg2320]

I've heard replacing the coil and ignition pickup could help as well. Any thoughts on this ?

 

[Bondo]

I've heard replacing the coil and ignition pickup could help as well. Any thoughts on this ?

Ayuh,..... Those are 2 parts that either they work,................. or they don't,......

Millions of prefectly good coils are changed every year, only because it's Easy, 'n no other reason,......