engine troubles? questions at least...

[TitanTn]

I'll try to make a long story reasonably short:

I pulled my 1986 7.4L PCM inboard motor early this winter to do some work on the boat. The engine ran great last year, but while it was out, I wanted to "tune" it up. I stripped all the accessories, cleaned and painted everything. The manifolds are in great shape. Almost look new (I've had the boat for about 18 months). Replaced valve cover gaskets, engine water pump, hoses, belts, plugs, etc. Pulled the carburetor and replaced the accelerator pump. Cleaned everything real well and it all went back together real nice.

Then trouble struck. When lifting the engine to put it back, a chain quick-link broke and the engine fell. Fortunately no one was injured. The oil pan took the worst of it. I pulled the pan and because of the new pan I had to buy a new oil pick-up screen. New gaskets and everything was back together.

Got the engine back in the boat and everything connected. Started it up for the first time today. Apparently the raw water pump pulley slammed into the ground because it's wobbly, and presumably bent. Other issues include, initially a little smoke around the starboard exhaust manifold. It seemed to dissipate after a while. Not sure. The starboard manifold barely got warm. The port one heated up as you'd expect. The engine warmed up to temp and held, but the manifolds were never the same temp. The carb seemed to do okay, but isn't perfect. I'm not sure if it'll get better with some running or if it needs adjustment. I've mechanically inclined, but I've never done much carb tuning and have no idea where to begin.

So I'm looking for advice, thoughts, suggestions, etc., on any and all of these issues. So chime in on anything:

- raw water pump rebuild or replacement
- smoke
- manifold temps
- carb issues

Thanks for any and all help. Here is a video I took tonight. You can see the date pump pulley wobble. It's worse in person and when the engine is running a little slower. http://youtu.be/fnnE1Kw2E8Q?hd=1

 

[Bondo]

Re: engine troubles? questions at least...

Ayuh,... Welcome Aboard,....


The water pump needs fixin',... If it's the pulley, or the shaft is the question...

The smoke mighta been spillage,... donno...

The manifolds shouldn't get all that hot, 'n are rarely equal in temps....

The carb,..?? Which 1 is it,..??

 

[TitanTn]

Re: engine troubles? questions at least...

Ahh, good point. It could be the shaft OR the pulley. I just assumed the worst cause that always seems to be my luck. I'll check into that.

Not sure about spillage. I was pretty neat and not aware of any spillage. Hopefully that's the case.

The port manifold is not getting all that hot, but it is as hot as it should be. The starboard side is barely warm. The water coming out the back is the same. Very warm water from the port side and barely warm water on the starboard side.

I'm not exactly sure of the carb model, but it's a 4 barrel Holley that came on this engine in 1986.

 

[TitanTn]

Intermittent starting issue

Intermittent starting issue

The engine will turn over the first 2-3 times I turn the key, but then... nothing. I then have to wait for 2-4 minutes and it'll turn over again. Sometimes after running a while the issue will happen on the first key turn. What should I check first? The engine is a 7.4L inboard. Thanks.

 

[TitanTn]

Re: engine troubles? questions at least...

To whichever moderator moved my posts: thanks for nothing.

My posts are not specific to a make of marinized engine. Unfortunately there is not a forum to just talk about engine issues unrelated to a specific brand. So my options are to put a general engine question in a forum that gets traffic and therefore means I might get help, or put it in an "other brand" category. There's no reason I should not get general help on engine issues just because I'm not running the forums preferred engine brand. I guess I've just learned to "say" I have a Mercruiser so I can get general engine help. It's just my opinion but this seems to be over-moderation in a poorly designed forum setup.

 

[Bondo]

Re: engine troubles? questions at least...

To whichever moderator moved my posts: thanks for nothing.

Ayuh,.... Yer Welcome....

I didn't design the forums, nor did I write the rules....
I Volunteered to help the Mod Tea almost a year ago,...
I'm a Mechanic, not a geek, so the Best I can do 'round here is to delete spam, 'n move misplaced threads....
There used to be 1 forum for the I/Os, then things were split up...
If yer thread were left in the Mercruiser forum, it wouldn't fallen off page 1 in no time, 'n you'd Never get a response...
All of the forums are rather slow this time of year, not just this 1...

Did I mention, I didn't write the rules or design the forum,..??

If you'd like, I'll hook ya up with the rest of the Mod Team, 'n you can take it up with them....

I also merged yer starin' question, as We can discuss it here, if you'd like,...
It'll make it easier to follow just exactly What We're workin' on, as it Ain't anything close to bein' a Mercruiser dressed BBC...

For the sake of conversation, 'n it's to cold in my garge to get anything done this afternoon,...

The port manifold is not getting all that hot, but it is as hot as it should be. The starboard side is barely warm. The water coming out the back is the same. Very warm water from the port side and barely warm water on the starboard side.

As I said, due to balance, or lack there of, in the T-stat housing's water flows,...
The manifolds are rarely to never the Same temps....
Maybe the unused raw water is all goin' to the cooler side,.. Donno...
It's a Non-issue, seein' you just inspected the manifolds, 'n risers...

I'm not exactly sure of the carb model, but it's a 4 barrel Holley that came on this engine in 1986.

This is Why I moved this outa the Mercruiser forum,... Merc Never, Ever used a Holley carb,....
'n I don't know what PCM used.... If it's original, there oughta be numbers on it, Somewhere.....
You had it apart,.. Did you Rebuild it,..?? I'd Guess it'll need to be set-up, 'n adjusted, because ya had it apart...

The engine will turn over the first 2-3 times I turn the key, but then... nothing. I then have to wait for 2-4 minutes and it'll turn over again. Sometimes after running a while the issue will happen on the first key turn. What should I check first?

You have a loose/ corroded wiring end Somewhere...
Start at the battery, 'n work yer way through the starting circuit to the starter...
Do Both the positive, 'n Ground legs...
Things need to be shiny metal Clean,... Not just "Looked" at...

Again,... Bein' a PCM, 'n Not a Merc. I'm not sure what you've got,...
I'd Guess it mirrors a Merc. with the battery voltage to the starter solenoid, 'n the key circuit runnin' through a slave solenoid....
Again, Donno...

Sorry yer experiences here ain't been the Best, but it IS the s l o w time of the season....

Happy Superbowl Sunday.....

 

[TitanTn]

Re: engine troubles? questions at least...

Bond-o - Thanks for your replies. I still don't agree with the forum setup, but I'm not interested in pursuing it unless the forum owners are interested in constructive feedback. Otherwise, it's a waste of time.

I'm glad to hear you say that the different manifold temps is a non-issue. I'm not sure that it was like this before, but I'm thinking it's okay if the overall engine temp is within specs.

I've owned many Mercruiser engines, and I think the overall setup is extremely similar to the PCM. I think your comment on the ground wire is an extreme possibility and will be confirming that I'm getting a solid connection everywhere, but focusing on the grounds.

I had the carb off the intake while painting. While it was off, I replaced the accelerator pump and just cleaned the carb as best I could. I haven't pulled anything else apart on the carb. It ran great last year. I would just like some thoughts on basic carb adjustment. At this point I'm not looking for something specific to my model of carb, but just carb adjustment "basics."

The Super Bowl was fun to watch even though I didn't have a horse in the race.

 

[Bondo]

Re: engine troubles? questions at least...

I had the carb off the intake while painting. While it was off, I replaced the accelerator pump and just cleaned the carb as best I could. I haven't pulled anything else apart on the carb. It ran great last year. I would just like some thoughts on basic carb adjustment. At this point I'm not looking for something specific to my model of carb, but just carb adjustment "basics."

Ayuh,.... There's lotsa Basic carb settings, such as the float levels, needle heights etc. done Inside the carb...

The Only Basic settings available on the outside of the carb is the idle air screws, 'n the idle stop screw...

I don't do Holleys, so I'm not up on just where ya oughta be lookin'....

 

[RogersJetboat454]

Re: engine troubles? questions at least...

Since we currently can't post pictures, how about a description of your Holley.

Is there a single accelerator pump, or two? If it is a single in the front then chances are you have a 4160 based carb with vacuum secondaries. If it has one on the front and rear float bowls then you have a 4150 double pumper based carb. Holley used either center hung or side hung floats. The height is adjusted with a set screw and lock nut (big flat head screws with thin nut on the top of the float bowls).

Idle mixture jets on a typical Holley are two very small flat head screws with springs behind them, and are located on either side of the metering block that goes between the front float bowl, and the main body of the carb. You typically adjust these with the vacuum gauge method of dialing in a carb. Float height on most Holleys is set externally. There are brass sight plugs that you remove out of the side of the float bowl (about 3/4 of the way up), and adjust the floats till there is barely a dribble out of these holes.

If you want to know more about the carb, there should be a "list" number stamped on the air horn for the choke. Last I checked, there were several places to look up the list number (Holley web site may be included).

If you have not rebuilt the carb, it may not be a bad idea to do so. Holley gasket kit's are dirt cheap, as long as you get the right one for your carb. Holley's are about the simplest 4 barrel carb you will see out there.

 

[TitanTn]

Re: engine troubles? questions at least...

Thanks Rogers. That's very helpful. I'm out of town on a business trip right now, but when I return I'll determine exactly which carb I have.