wishingtobeonthewater
Recruit
- Joined
- Sep 1, 2020
- Messages
- 2
Engine Model: MCM 4.3 LX GEN+
Engine serial #: 0K161255
Boat is a 1997 model hull.
Hello Everyone,
New to the forum but I have experience with mechanical and electrical systems. This is my first boat, but I have worked on cars and motorcycles.
So, as the title says, my mercruiser is stalling after an undetermined amount of time. Seems to stall quicker when the engine is warm. Also, seems to stall even above idle rpm. The engine starts almost first crank every time, even after stalling.
Compression test:
I ran a compression test... and wasn't happy with the result. There is around 120-130 PSI in each cylinder. However I didn't have the throttle at WOT and only removed one spark plug at a time (compression checked with the other spark plugs in). Not sure if the WOT and removing all plugs for the test will improve the result.
I'm really hoping I don't have to replace the piston rings or head gasket, but I'm trying to prepare myself for that if needed.
Items I'm planning on checking:
1) I plan on shorting the oil pressure switch to see if the stalling will stop. If so I'll get a new switch.
2) Fuel pump PSI, I just bought the gauge for checking this, so I plan on putting it on the fuel pump line and cranking the starter to see PSI.
3) Check the timing, don't have the timing light tool yet though.
I was hoping to get some insight from some more experienced mechanics. Especially if there are any easy to follow guides for piston ring replacement (hopefully I won't need to do this though).
I'm thinking the engine is warming up, block expands a little, which makes the compression worse in each cyclinder, causing engine stall.
However, I'm hoping the issue is a simple corroded ground or something. I've already restored the rest of the boat and trailer, so this is my last hurdle before heading out to the water for the first time.
Thanks for any information!
Engine serial #: 0K161255
Boat is a 1997 model hull.
Hello Everyone,
New to the forum but I have experience with mechanical and electrical systems. This is my first boat, but I have worked on cars and motorcycles.
So, as the title says, my mercruiser is stalling after an undetermined amount of time. Seems to stall quicker when the engine is warm. Also, seems to stall even above idle rpm. The engine starts almost first crank every time, even after stalling.
Compression test:
I ran a compression test... and wasn't happy with the result. There is around 120-130 PSI in each cylinder. However I didn't have the throttle at WOT and only removed one spark plug at a time (compression checked with the other spark plugs in). Not sure if the WOT and removing all plugs for the test will improve the result.
I'm really hoping I don't have to replace the piston rings or head gasket, but I'm trying to prepare myself for that if needed.
Items I'm planning on checking:
1) I plan on shorting the oil pressure switch to see if the stalling will stop. If so I'll get a new switch.
2) Fuel pump PSI, I just bought the gauge for checking this, so I plan on putting it on the fuel pump line and cranking the starter to see PSI.
3) Check the timing, don't have the timing light tool yet though.
I was hoping to get some insight from some more experienced mechanics. Especially if there are any easy to follow guides for piston ring replacement (hopefully I won't need to do this though).
I'm thinking the engine is warming up, block expands a little, which makes the compression worse in each cyclinder, causing engine stall.
However, I'm hoping the issue is a simple corroded ground or something. I've already restored the rest of the boat and trailer, so this is my last hurdle before heading out to the water for the first time.
Thanks for any information!
