couple mercruiser questions

[redneck joe]

Replaced the spark plugs today; had not done so since I bought the boat (yeah I'm an idiot). Two were only hand tight - When I put the socket on them to 'find' them I was able to not put the ratchet on and just take them out. What performance issues could this cause?

Also - I've been stalling at low speed (like trailering/docking). My air cleaner was a mess. A total mess. Could this be a contributing factor? Seemed to run fine when cold/cool but not after the block got good and warm to the core.

Found some oil on the bottom of the starboard riser. Where could this be coming from? Only put in a quart ar two each season I've had it (maybe 100 hours each).

 

[muc]

Loose spark plugs will cause the plug to run too hot because it can't transfer heat as well as it should. A plugged flame arrester will cause engine to run rich because it's like the choke is stuck on. Find where to oil is coming from.

 

[redneck joe]

yeah thought so on the flame arrestor, news on the spark plug and of course on the oil any ideas? If valve cover should burn off when it hits the exhaust?

 

[MikDee]

Oil in riser? Maybe worn valve guide seals leaking some oil into the exhaust?

 

[redneck joe]

no sir the oil was on the outside of the riser, on the underneath. I discovered when changing the rear starboard plug. Speaking of which, there was acually more oil back there and almost none towards the front




rj

 

[MikDee]

I see, then it's likely to be a valve cover gasket. Your pcv hose is on the right side valve cover, no? do you think you maybe getting a bit of seeping from there?

 

[midcarolina]

The low speed stalling while trailering/docking.........could be an issue with the shift interrupt, as those activities usually require in gear to neutral shifts......

or you idle is set a tad low...

 

[redneck joe]

I see, then it's likely to be a valve cover gasket. Your pcv hose is on the right side valve cover, no? do you think you maybe getting a bit of seeping from there?

yes actually if the pcv valve is what I think I have two coming off the breather, one to each side. Didn't notice any oil on top of the valve cover but then it would probably be just a small 'line' of oil from there down so might be easy to miss. I'll check today when I go back to work on it. And thinking - the pcv valve isn't it supposed to have something in it that rattles? Both mine are just empty tubes where is goes into the valve cover.

Seems like it would have to hit the exhaust manifold along the way though and I would smell burning oil?




rj

 

[redneck joe]

The low speed stalling while trailering/docking.........could be an issue with the shift interrupt, as those activities usually require in gear to neutral shifts......

or you idle is set a tad low...

Sorry I wasn't too clear - the stalling happens after the shift -- I can be in gear fine for 2-45 seconds then just dies and actually the idle is too high @ about 1100. I need to learn how to adjust. Not a mechanic, but I can usually figure stuff out.



rj

 

[MikDee]

yes actually if the pcv valve is what I think I have two coming off the breather, one to each side. Didn't notice any oil on top of the valve cover but then it would probably be just a small 'line' of oil from there down so might be easy to miss. I'll check today when I go back to work on it. And thinking - the pcv valve isn't it supposed to have something in it that rattles? Both mine are just empty tubes where is goes into the valve cover.

Seems like it would have to hit the exhaust manifold along the way though and I would smell burning oil?




rj

Actually boats don't use PCV valves, just a hose from the valve cover to the carb.

 

[Bondo]

yes actually if the pcv valve is what I think I have two coming off the breather, one to each side. Didn't notice any oil on top of the valve cover but then it would probably be just a small 'line' of oil from there down so might be easy to miss. I'll check today when I go back to work on it. And thinking - the pcv valve isn't it supposed to have something in it that rattles? Both mine are just empty tubes where is goes into the valve cover.

Seems like it would have to hit the exhaust manifold along the way though and I would smell burning oil?




rj

Nope, not with water cooled manifolds, they don't get near hot enough,....

 

[redneck joe]

10-4. I just got back from jacking with the PO's wiring (and add to that i'm not great at it) been a challenging day but anytime on the boat, even just on the trailer, is good. I did see where there was a 'historical' oil path from the top of the valve cover. I'll check it next time I run for a good amount of time to see if it becomes 'fresh'.


off to order some boat part, hope iboats has them.



rj

 

[NHGuy]

To be able to change your spark plugs you'll need to grind down the outer section of a plug socket. This is needed because the water jacket exhaust manifolds get in the way of a normal spark plug socket. If you don't it's really easy to break the ceramic insulators. Here's an illustration

 

[redneck joe]

all is well, runs much better at low speeds (too fast in gear at idle speed) and started much better. Find the oil and the overheat issue next but good few hours out.