No spark

[kaiasdad]

It started out as an idle issue, I had to keep giving the thottle a "bump" just to keep it from dying at idle (between 600-700 rpm. Then we took a run up river from Lake Havasu to the sandbar, on the way there I couldn't get it to WOT and it was hestitating at about 3200 rpm and wouldn't give me any more power at the point so we basically jogged it to the sandbar. Right when I get there it dies on me completely, battery cranks like a champ (dual optima blue tops both new), full tank and would not fire even when the carb was primed. Any ideas where to troubleshoot first? It's a 5.7 blue water merc (just serviced and the wife is pissed bcus everytime we go to Havasu this happens). Compression is 150-152 in all cylinders cleaned all plugs and checked gap, cap and rotor were clean. Need some help before our summer is spent trying to dump the boat.

[JayHoy]

Do you still have points??? Whats the condition of them? Out of adjustment possibly,or frosted over? A upgrade to a igniter kit maybe in order, well worth the $150 imo

[Sunsetter95]

Yes it would be a good idea to go to electronic ignition... but, point ignition is OK as long as everything is kept in good condition.

A few things:

Have you changed the fuel filters?

Have you changed the points, condenser, cap, and rotor?

Does the coil produce a good spark? They fail when the get hot usually.

Does the rotor point to the correct cap post at top dead center? Timing chain jumped...

If it starts and runs "ok" cold, it most likely will be heat related. Again coil, condenser...

Has the carb been rebuilt in the last couple of years? But you did say it would not fire even with a manual prime...

Are all engine and electrical system grounds clean?

When I bought mine from the original owner, I just replaced everything, but then again, I also had the engine rebuilt.

[kaiasdad]

Do you still have points??? Whats the condition of them? Out of adjustment possibly,or frosted over? A upgrade to a igniter kit maybe in order, well worth the $150 imo

points are good and the weather is very mild here never gets colder than maybe 50 degrees even in the winter. What would the igniter kit do for me though? I had thought of switching to an electronic ignition when I replaced the coil last year but my mechanic said I would just introduce a bunch of other problems into the mix.

[kaiasdad]

Yes it would be a good idea to go to electronic ignition... but, point ignition is OK as long as everything is kept in good condition.

A few things:

Have you changed the fuel filters?

Have you changed the points, condenser, cap, and rotor?

Does the coil produce a good spark? They fail when the get hot usually.

Does the rotor point to the correct cap post at top dead center? Timing chain jumped...

If it starts and runs "ok" cold, it most likely will be heat related. Again coil, condenser...

Has the carb been rebuilt in the last couple of years? But you did say it would not fire even with a manual prime...

Are all engine and electrical system grounds clean?

When I bought mine from the original owner, I just replaced everything, but then again, I also had the engine rebuilt.

Yeah fuel filter is new, points are good, coil is brand new Accel coil I replaced last year. It is a bit of a hard start (maybe two or three tries and she fires up), carb was rebuilt last year and cleaned it up before I took it out and had the mech check my cap and rotor (checked out ok). This boat is pretty much new from the pan up as far as the engine goes. I gotta figure this out bcus it's pretty embarrassing to have your bu towed by a 78 Dana cruiser