5.7GLI slight vibration at idle and knocks 2500-3300 rpm

[TexasCobaltGuy]

Took the Boat out for the 1st time this weekend and it hasn’t gone so well...

Right off the jump it got hot so I replaced the sea pump impeller (I knew better. )

With new impeller it gets up to 195-205 range in temp but doesn’t overheat. I am pretty sure that is normal range.

Now it vibrates at idle like a misfire and if I accelerate it knocks.

Had a full tank of gas over the winter but a good 35gal of it is probably at least a year old (and has Ethanol ) I suspect so picked up the starbrite marine fuel treatment but because it is full I didn’t run a fill up down after the treatment so hopefully it gets down to the tank)

Anyway so trying to figure out what to do next...
- Spark plugs and wires
- valves
- lifters
- distributor
- fuel pump
- fuel filter
- fuel
???

Thanks in advance

[Big Block Power]

Boats normally run around the 170 range. It's not like a car. Do a compression test first. If you pull plugs what do they look like.

[TexasCobaltGuy]

Operating temp wonder if it is accurate

[Big Block Power]

Operating temp wonder if it is accurate

Prob. Or get a infrared temp gun. It prob has a 170 tstat. Change that.

[TexasCobaltGuy]

What site do you use to lookup and purchase parts? Volvopentastore.com or something else?

[Big Block Power]

Try this.
I use Google
http://www.marinepartsexpress.com/onelist.php?ID=164

[TexasCobaltGuy]

Quick add on. Taking the boat home today to work on it in the driveway. To be able to start and idle are earmuffs over the intake connected to hose adequate water supply? Or do I need something more?

[Big Block Power]

Quick add on. Taking the boat home today to work on it in the driveway. To be able to start and idle are earmuffs over the intake connected to hose adequate water supply? Or do I need something more?

Yes. But if you put it in gear you won't go anywhere.

[TexasCobaltGuy]

Also if I wanted to add inline hose connection to the intake to the sea pump anyone have any recommendations for a kit to add that?

[TexasCobaltGuy]

Boats normally run around the 170 range. It's not like a car. Do a compression test first. If you pull plugs what do they look like.

1= 150
3= 30
5 = 30
7 = 150

2 = 150
4 = 90
6 = 30
8 = 150

[akorcovelos]

Boats normally run around the 170 range. It's not like a car. Do a compression test first. If you pull plugs what do they look like.

1= 150
3= 30
5 = 30
7 = 150

2 = 150
4 = 90
6 = 30
8 = 150

If these numbers are right that engine is done.You can do a leak down to see if it's top or bottom end, but being both banks it's likely bottom end.

[Big Block Power]

Boats normally run around the 170 range. It's not like a car. Do a compression test first. If you pull plugs what do they look like.

1= 150
3= 30
5 = 30
7 = 150

2 = 150
4 = 90
6 = 30
8 = 150

If these numbers are right that engine is done.You can do a leak down to see if it's top or bottom end, but being both banks it's likely bottom end.

Could have popped both head gaskets. Cracked block on both sides. Don't think so. Pull the heads pal.

What state was this boat in? If it's Texas it froze. Sorry I hate buying boats from Texas. They never think they have to winterize and they always freeze. So common.

[akorcovelos]

1= 150
3= 30
5 = 30
7 = 150

2 = 150
4 = 90
6 = 30
8 = 150

If these numbers are right that engine is done.You can do a leak down to see if it's top or bottom end, but being both banks it's likely bottom end.

Could have popped both head gaskets. Cracked block on both sides. Don't think so. Pull the heads pal.

If he's lucky yeah head gaskets. Being the center 2 cylinders on both banks there's hope as the gaskets usually pop between the middle cylinders. Either way, it's a top end tear down, bummer.

[Big Block Power]

If these numbers are right that engine is done.You can do a leak down to see if it's top or bottom end, but being both banks it's likely bottom end.

Could have popped both head gaskets. Cracked block on both sides. Don't think so. Pull the heads pal.

If he's lucky yeah head gaskets. Being the center 2 cylinders on both banks there's hope as the gaskets usually pop between the middle cylinders. Either way, it's a top end tear down, bummer.

Yep hoping the knocking noise isn't the bottom end.

[TexasCobaltGuy]

I am pretty handy and not afraid of a challenge and have done work on my sons 95 impala SS (replaced Opti-spark, Fuel Injectors, Cats, etc) but I have never torn down an engine.

I would love to save the couple thousand in labor so curious if this is a decent DIY project I can handle. "Especially with all this at home time lately with the Stay at home orders"

Do you have any recommendations on sources for good instructional items, videos, maintenance manuals etc?

In talking to the dealership over the phone they guessed it would probably run ~3k for everything. And if they sell me the parts it will be ~1k (that might include the cost of having the heads resurfaced and magniflux done, not sure I was still trying to get over the 3K when he was going thru the other options...).

This boat has been in our family since 99 or 2000, and it overheated many years back to the point that the paint burnt off one side of the exhaust manifold, the dealership had left something loose in the cooling system and it broke loose and overheated badly (I wasn't there this was my dad's recollection). The dealership fixed it but not sure exactly what all they did besides repaint and tight things back up? It only has 269 hours and generally has ran great but I did notice a slight vibration last season from the engine which is worse now but it still can run but the big difference this season is under load it knocks...

So after the compression tests and googling, I have seen a few articles about overheating and experiences where the head gasket between the 2 middle cylinders fails.

I have checked the oil and see NO signs of water in the oil, I just got my oil drain pump yesterday from amazon so I was going to drain the oil today after the rain stops and if that is clean I have decided I am going to tackle this myself (which the guidance and help of you guys of course! Thank you in advance BBP and others for your assistance!)

So I will be taking lots of pictures and maybe a few short videos along the way and uploading them to this thread as I work thru this...

So the 1st hurdle is... Can I get the distributor out of the motor without pulling the engine?


Thanks in advance for any help.