PLEASE HELP!!
I have a 2006 Maxum 1800mx with a Mercruiser 3.0 Inboard engine with the Delco EST ignition system.
Just for background info - we bought the boat brand new in 2007, so no previous owners or aftermarket modifications etc. The engine is as standard, and has done no more than 15-20 hours in Sea Water of the coast of the UK.
The problem- the engine is very very difficult to start, last weekend I tried to start but just heard a clicking noise, replaced battery and still same problem. I eventually traced problem to a bad connection in the battery isolator switch (red key breaking the positive terminal from battery) and once replaced the boat cranks but would not start.
Next we drained the fuel tank and put 20 litres (4 gallons) of fresh petrol (just incase this had an effect) but still no luck. When removing the air filter I could see fuel squirting into the carb.
Next we replaced the spark plugs x4 with the exact same that have been on the boat from delivery from the factory when new.
Next we gave the carb some (easy start) and still it kept cranking.
I ensured that the boat was level on the trailor when starting as I noticed that the back plug (nearest the prop) seemed to be wetter than the front plugs when the boat was at a slight angle when hitched to the car, so I unhitched the trailor and made the boat engine level. ( I am not sure if having the boat level makes a difference but I tried that just in case)
After leaving the boat for some time it did eventually start, the water flushed out looked a little orange but nothing you wouldnt expect after being idle for about a year or so.
I let the boat idle for about 30 mins and engaged forward and reverse and revved while in neutral. I switched the engine off, then on, then off etc and it worked perfectly. However after switching the engine off to go for a 30 min break, upon returning the engine wouldnt start. Just kept cranking and cranking, even with aero start in the carb. Eventually like last time it fired up and ran fine.
This is very very strange as it sometimes starts and sometime doesnt.
My next steps of attack are;
1. Test for a spark when the engine wont start again. I have bought a spark tester, a tin of carburettor cleaner just incase the jetts are blocked up.
2. I have a mercruiser manual for the engine, where I will be testing the coil, ignition module and pickup coil. I will post the results on here but have a feeling that they are all fine as it does run sometimes
Before I start these tests, can anyone suggest anything else? Certain people have said to check the carb to see if the choke is sticking on, others say to check for bad connections etc??
I may be jumping the ahead slightly, but when checking to see that all wires where not loose I noticed a switch that is situated on top of the shifter plate (where all the mechanisms are for selecting forward and reverse). I believe it is called a 'shift interuptor switch', and primarily stalls the engine whilst running to allow the selection of neutral from forward or reverse position, I checked this switch using my ohm meter and seems to be working fine, however, whilst doing some google searches on this switch, it appears that if you where to alter the timing of the engine, if you follow the manufacturers and many procedures online exactly, it specifically says to disconnect the wires to this switch, and bypass the switch by connecting the harness wires together (bypassing switch), when I did this it causes the engine to stall (apparently it is just supposed to reduce the revs), now surely this is something that cant be right on my engine, how on earth am I supposed to set the timing on the engine if it stalls when I bypass the shift interuptor switch? The only difference I did compared to when you set the timing according to mercruiser manual is that when I connected the two wires together (bypassing the shift interuptor switch), I did not also ensure that a jumper lead was inserted to connect the two normally hanging free wires from the ignition module (apparently this puts the engine into base timing). Personally I cannot see how connecting those two wires from the igniton module would stop the engine stalling when the shift interuptor switch is bypassed. But I may be incorrect? Just some further info? Maybe my timing is so out that its causing the engine to stall when bypassing the shift interuptor, but his is just my theory and limited knowledge so please dont quote me on it????
Any suggestions as to what to do next would be greatly appreciated, sorry about all the long text but want to fill you in with all info!!
Cheers Dave!!
I have a 2006 Maxum 1800mx with a Mercruiser 3.0 Inboard engine with the Delco EST ignition system.
Just for background info - we bought the boat brand new in 2007, so no previous owners or aftermarket modifications etc. The engine is as standard, and has done no more than 15-20 hours in Sea Water of the coast of the UK.
The problem- the engine is very very difficult to start, last weekend I tried to start but just heard a clicking noise, replaced battery and still same problem. I eventually traced problem to a bad connection in the battery isolator switch (red key breaking the positive terminal from battery) and once replaced the boat cranks but would not start.
Next we drained the fuel tank and put 20 litres (4 gallons) of fresh petrol (just incase this had an effect) but still no luck. When removing the air filter I could see fuel squirting into the carb.
Next we replaced the spark plugs x4 with the exact same that have been on the boat from delivery from the factory when new.
Next we gave the carb some (easy start) and still it kept cranking.
I ensured that the boat was level on the trailor when starting as I noticed that the back plug (nearest the prop) seemed to be wetter than the front plugs when the boat was at a slight angle when hitched to the car, so I unhitched the trailor and made the boat engine level. ( I am not sure if having the boat level makes a difference but I tried that just in case)
After leaving the boat for some time it did eventually start, the water flushed out looked a little orange but nothing you wouldnt expect after being idle for about a year or so.
I let the boat idle for about 30 mins and engaged forward and reverse and revved while in neutral. I switched the engine off, then on, then off etc and it worked perfectly. However after switching the engine off to go for a 30 min break, upon returning the engine wouldnt start. Just kept cranking and cranking, even with aero start in the carb. Eventually like last time it fired up and ran fine.
This is very very strange as it sometimes starts and sometime doesnt.
My next steps of attack are;
1. Test for a spark when the engine wont start again. I have bought a spark tester, a tin of carburettor cleaner just incase the jetts are blocked up.
2. I have a mercruiser manual for the engine, where I will be testing the coil, ignition module and pickup coil. I will post the results on here but have a feeling that they are all fine as it does run sometimes
Before I start these tests, can anyone suggest anything else? Certain people have said to check the carb to see if the choke is sticking on, others say to check for bad connections etc??
I may be jumping the ahead slightly, but when checking to see that all wires where not loose I noticed a switch that is situated on top of the shifter plate (where all the mechanisms are for selecting forward and reverse). I believe it is called a 'shift interuptor switch', and primarily stalls the engine whilst running to allow the selection of neutral from forward or reverse position, I checked this switch using my ohm meter and seems to be working fine, however, whilst doing some google searches on this switch, it appears that if you where to alter the timing of the engine, if you follow the manufacturers and many procedures online exactly, it specifically says to disconnect the wires to this switch, and bypass the switch by connecting the harness wires together (bypassing switch), when I did this it causes the engine to stall (apparently it is just supposed to reduce the revs), now surely this is something that cant be right on my engine, how on earth am I supposed to set the timing on the engine if it stalls when I bypass the shift interuptor switch? The only difference I did compared to when you set the timing according to mercruiser manual is that when I connected the two wires together (bypassing the shift interuptor switch), I did not also ensure that a jumper lead was inserted to connect the two normally hanging free wires from the ignition module (apparently this puts the engine into base timing). Personally I cannot see how connecting those two wires from the igniton module would stop the engine stalling when the shift interuptor switch is bypassed. But I may be incorrect? Just some further info? Maybe my timing is so out that its causing the engine to stall when bypassing the shift interuptor, but his is just my theory and limited knowledge so please dont quote me on it????
Any suggestions as to what to do next would be greatly appreciated, sorry about all the long text but want to fill you in with all info!!
Cheers Dave!!