2004 mercruiser 4.3 TKS will not hot restart

[Yokane]

You
Starts perfectly cold. Let it run at idle for 10 mins as per manual to warm up to operating temp. Motor forward at 5 knots to go to marina. Put in neutral when coming alongside. Engine cuts and will not restart.

This only happens when engine has warmed up from cold. If engine has been running after a run. It will start perfectly everytime.

Merc carb taken off and cleaned, new fuel filter.

 

[alldodge]

Check the shift interrupter switch adjustment
Then check to see if carb is flooding

 

[Yokane]

What's best way to restart hot engine if it has flooded?

Normal start does not work until engine has fully cooled.
1/4 throttle does not work.

I have just read about wide open throttle so will try that tomorrow.

 

[alldodge]

The key is to find out why its not starting, and yes if its flooded, then WOT is the way

If its flooding, you should see fuel dripping down the carb during idle and for a short time when turned off

 

[Yokane]

I may have the answer. When I got the boat at the start of the season it was all serviced ready to go. When I started it up first time on the water I was not allowing it to warm up fully on the first cold start. I only read about the 6-10 recently after reading the forums and manual. I'm too used to outboards.

Therefore when I used it first time and went from mooring to the marina and went to idle back it cut out . I rang the dealer and thought the idle needed to be set higher higher s it struggled to maintain the 650 idle revs.

I then tuned it up to 800 revs

Since then I have been cold starting it and allowing to warm up for the full 10 mins but the problem above kept happening. The annoying part being unable to restart at all.

2 days ago I lowered the revs back to 650 and allowed it the full 10 mins to warm up.

No cutting out when I idle back and it holds nicely and idles at 650.

Is this the issued solved or do I just think its solved?

Would the starting at 800 revs be causing it to flood or miss a stage of the start up process?

I have not been unable to test if I have solved the "unable to restart hot" with wide open throttle, as now it doesn't cut out!!!

 

[Yokane]

Scrap the above! Same thing happening. Warmed up engine and once warm after 10 mins went from mooring to marina which is 200ft away to pick up people and it cuts out as soon as I lut it back into idle.

Tried to restart and will not fire up.

Tried wIde open throttle and nothing.

There is fuel in the carb and i pumped and could see the two fuel jets in the carb working so there is fuel.

Any ideas??!!

 

[TunaFish389]

When your out bring a timing light.. When issue happens see if you are getting spark. You can still see if you are getting spark even if engine doesnt start... My money is on that your not getting spark, but dont know your system well, only that it is electronic ignition.

 

[alldodge]

Letting the motor warm up or not warm up has no impact on if it will start or not. We all know you need spark, but if the carb is flooding the motor will not start very easy, if at all.

Check the shift interrupter switch, if its staying closed it will kill the motor. When it does it and will not start disconnect one side of the switch, or pull the right side plug from the distributor. If it first right back up then its the switch

 

[TunaFish389]

I had issue with electronic ignition when engine was warmed up. So yes warming up might have an effect on starting. Turns out the the ignition was overheating and stop sending spark to the plugs.. Cooled down and all was well.

 

[Yokane]

You are right nothing to do with whether engine is warm or not. The TKS hissing until it gets to 150 F after about 12 mins and the motor then idles quietly away at 650 revs. Put into gear brought it back to neutral after 10 feet of motoring and cuts out. Will not restart so it back to checking spark and shift interruptor next.

 

[Yokane]

Ok I'm getting spark when warm. Carb is not flooding.

will check switch on the water tomorrow