I've got an 01 Mercruiser 502 that is giving me trouble starting. If the boat sits for any period of time over a hlf hour I have to throttle it half throttle to get it started.
When it is shut down for less than a half hour it starts right back up with no problem??? Anybody have any similar issues?
99% chance you have the wrong size intake valves. There was a short period of time where 2.190 valves were put in heads cut for 2.250. The symptoms are when it sits after running it wont start and the throttle has to be opened. Run it on the trailer for 10 minutes then do a leakdown, if the valves are incorrect, it will leakdown 70% to 90% past the intake valves.
We have fixed many of these..... including mine when they were stock 502's.
So they installed the 'MAG' valves in HP heads, and put the HP heads on the MAG engines ?
Wow !!!
Never ran a wrong valve size for the seat........I would think it would give you more problems than hard start.
Never heard of this Merc issue. Thanks for mentioning it.
99% chance you have the wrong size intake valves. There was a short period of time where 2.190 valves were put in heads cut for 2.250. The symptoms are when it sits after running it wont start and the throttle has to be opened. Run it on the trailer for 10 minutes then do a leakdown, if the valves are incorrect, it will leakdown 70% to 90% past the intake valves.
We have fixed many of these..... including mine when they were stock 502's.
Engine has 160hrs, The previous owner of this boat said it always ran perfect and allways started on the first turn of the key. I was just thinking it was sitting too long with out running and possible the injectors may be clogged.
What kind of ball park $$ for a fix if this Valve issue was the problem? Thanks for the info BD.
pull the little vaccum line off the fuel pressure regulator on the injector rail. turn the key on and see if it shoots out fuel from the regulators nipple. if it does, you need a new regulator. the new gen bbc's all had that trouble, be it boat or truck.
what happens is the fuel bypass's the ruptured fuel pressure regulator, goes up the vaccum line and into your intake manifold, flooding the motor. you'll only notice it when the motor is warm, motors like alot of fuel whens their cool'd off
Engine has 160hrs, The previous owner of this boat said it always ran perfect and allways started on the first turn of the key. I was just thinking it was sitting too long with out running and possible the injectors may be clogged.
What kind of ball park $$ for a fix if this Valve issue was the problem? Thanks for the info BD.
Guess how many times I have been told that!!The valve has such a small surface to seat on, it only seems to affect it when warm. Mine started showing the signs at around 60 hours and by 160 it was horrible and would only start warm with the throttle at 3/4... then I would have to let it run at 1200 for a few seconds then I could slowly let it come down to an idle. We fixed a few of these under warranty a few years ago.... all with the same complaint.
The leakdown and some other tests should be performed before tearing it apart to eliminate other possible problems. From your description it just sounds like that is the problem to me.
Impatient 1.... the fuel pressure regulator is on the fuel pump at the fuel cooler, not the fuel rails. They very seldom fail on these engines.
[QUOTE=BDMar;2926178]Guess how many times I have been told that!!
The leakdown and some other tests should be performed before tearing it apart to eliminate other possible problems. From your description it just sounds like that is the problem to me.
MAKES SENSE TO ME. Thanks for the advice I'll get in touch when I bring the boat back from Havasu.
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