CharlestonFX175
Cadet
- Joined
- Jul 20, 2009
- Messages
- 7
1997 Searay Searaydar FX16, with Merc SJ 175 XR2 that was rebuilt in 07 with a 2003 powerhead.
Dual Carb (not efi)
Last 2 summer seasons it ran well, except for sometimes it would be a bit finicky to start, toggling the throttle worked.
Over the winter(SC coast) I started engine about once every 3 weeks.
I did not seafoam the gas.
This season, from the first time out, been having problems.
For awhile, had some hesitations when opening to full throttle.
Perhaps varnish/gum deposits, used carb cleaner and seafoam in gas, after 4-5 hours of running, no longer having hesitation problems
However, having serious starting problems, only with boat in the water.
Starts almost perfectly on the trailer, cold or warm.
In the water, it's a different story. Very difficult to start:
When engine still cold, if I disengage the throttle and play it, then sometimes it will start.
Once I go out for 10 minutes plus, with engine warm, It no longer starts no matter what.
Been stuck out twice (sea tow to the rescue).
Varnish/Gum: I thought this maybe the problem, cleaned carbs with carb cleaner, and put a can of B-12 in tank.
Water in fuel: I poured fuel from tank into a cup, does not seam to be any water. Will install a fuel/water separator anyways.
Electric Idle fuel pump: Works fine. I installed a primer bulb anyways.
Fuel filter: It was pretty dirty, replaced with new.
New Plugs
Carbs were running a bit rich, leaned them up a bit (idle mixture screw).
Idle Enrichment Valve: Checked and seems to work fine, pumps fule and clicks.
Batteries are strong, charging system works.
Since all of the above has been done, it starts a "bit" better in the water, but still won't start when warm.
So, I'm still at: Engine fires up great on the trailer, idles a tad over 1000, yet starts very poorly when IN THE WATER only,
and is almost impossible to start IN THE WATER and warm.
Any help or ideas to diagnose or fix the problem is appreciated.
I'm wondering, could it be the impeller adds just enough load in the water, that the engine does not start?
Could a compression problem cause this?
Idle Thermal valve?
In the water, when started, the engine runs very very well, 5400 rpm at wop and running smooth.
The strange but important key is it starts fine out of water, and not when in the water.
Even when it does start in the water, for the most part, it won't hold it's idle for long, if at all. (must play with throttle)
And once warm (10 minutes running at 400 rpm+), when turned off, it is almost impossible to restart.
Thank you guys, any advice or priority diagnosis steps is appreciated.
Dual Carb (not efi)
Last 2 summer seasons it ran well, except for sometimes it would be a bit finicky to start, toggling the throttle worked.
Over the winter(SC coast) I started engine about once every 3 weeks.
I did not seafoam the gas.
This season, from the first time out, been having problems.
For awhile, had some hesitations when opening to full throttle.
Perhaps varnish/gum deposits, used carb cleaner and seafoam in gas, after 4-5 hours of running, no longer having hesitation problems
However, having serious starting problems, only with boat in the water.
Starts almost perfectly on the trailer, cold or warm.
In the water, it's a different story. Very difficult to start:
When engine still cold, if I disengage the throttle and play it, then sometimes it will start.
Once I go out for 10 minutes plus, with engine warm, It no longer starts no matter what.
Been stuck out twice (sea tow to the rescue).
Varnish/Gum: I thought this maybe the problem, cleaned carbs with carb cleaner, and put a can of B-12 in tank.
Water in fuel: I poured fuel from tank into a cup, does not seam to be any water. Will install a fuel/water separator anyways.
Electric Idle fuel pump: Works fine. I installed a primer bulb anyways.
Fuel filter: It was pretty dirty, replaced with new.
New Plugs
Carbs were running a bit rich, leaned them up a bit (idle mixture screw).
Idle Enrichment Valve: Checked and seems to work fine, pumps fule and clicks.
Batteries are strong, charging system works.
Since all of the above has been done, it starts a "bit" better in the water, but still won't start when warm.
So, I'm still at: Engine fires up great on the trailer, idles a tad over 1000, yet starts very poorly when IN THE WATER only,
and is almost impossible to start IN THE WATER and warm.
Any help or ideas to diagnose or fix the problem is appreciated.
I'm wondering, could it be the impeller adds just enough load in the water, that the engine does not start?
Could a compression problem cause this?
Idle Thermal valve?
In the water, when started, the engine runs very very well, 5400 rpm at wop and running smooth.
The strange but important key is it starts fine out of water, and not when in the water.
Even when it does start in the water, for the most part, it won't hold it's idle for long, if at all. (must play with throttle)
And once warm (10 minutes running at 400 rpm+), when turned off, it is almost impossible to restart.
Thank you guys, any advice or priority diagnosis steps is appreciated.