Cylinders Low In PSI ? (HELP)

BigDog98

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Re: Cylinders Low In PSI ? (HELP)

Thats bs, its either your gauge, or there may be fluid in the cyls.
That is what the mechanic told my friend. But the gauge is fine because i asked around and they all told me that the gauge brand is a good brand.
 

achris

More fish than mountain goat
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Re: Cylinders Low In PSI ? (HELP)

That is what the mechanic told my friend. But the gauge is fine because i asked around and they all told me that the gauge brand is a good brand.

Sounds like ANOTHER mechanic talking up work for himself.... :facepalm: I wouldn't worry about the high pressure until you have the manifolds and heads off and can have a look at what's going on... Once you do the leakdown test, record those numbers, then pull the heads. Have you pulled heads before? BTW, do you have the proper genuine manual for your engine?

Then take them to a machine shop for an overhaul.. While they are away, you can get in and clean up the rest of the engine ready for the heads to just go straight back on.... One tip... While you are pulling the engine apart, keep your eyes open... A lot of valuable information can be gleaned by what you see as it comes apart. What do the gaskets look like, were any of the bolts seriously stuck, or loose? Was there water (or oil) where there shouldn't have been, or a lack of it where it should have been? That sort of thing... Overlook nothing!

Also, give the manifolds and elbows a very serious inspection... Manifolds and elbows are those things that if you have ANY doubt about, toss 'em... And if you do end up tossing them (and give it's a 1991 engine it would almost be mandatory now) have a look at new dry-joint manifolds and elbows....

BTW... Just so we're clear, and not to lead you astray (any more than we are :lol:), I don't winterise because we don't get freezing temperatures where I am... If you get freezing weather you most definitely should be winterising....

Chris.........
 
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BigDog98

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Re: Cylinders Low In PSI ? (HELP)

Sounds like ANOTHER mechanic talking up work for himself.... :facepalm: I wouldn't worry about the high pressure until you have the manifolds and heads off and can have a look at what's going on... Once you do the leakdown test, record those numbers, then pull the heads. Have you pulled heads before? BTW, do you have the proper genuine manual for your engine?

Then take them to a machine shop for an overhaul.. While they are away, you can get in and clean up the rest of the engine ready for the heads to just go straight back on.... One tip... While you are pulling the engine apart, keep your eyes open... A lot of valuable information can be gleaned by what you see as it comes apart. What do the gaskets look like, were any of the bolts seriously stuck, or loose? Was there water (or oil) where there shouldn't have been, or a lack of it where it should have been? That sort of thing... Overlook nothing!

Also, give the manifolds and elbows a very serious inspection... Manifolds and elbows are those things that if you have ANY doubt about, toss 'em... And if you do end up tossing them (and give it's a 1991 engine it would almost be mandatory now) have a look at new dry-joint manifolds and elbows....

BTW... Just so we're clear, and not to lead you astray (any more than we are :lol:), I don't winterise because we don't get freezing temperatures where I am... If you get freezing weather you most definitely should be winterising....

Chris.........


Yes for sure the temperatures here in NY are 0 at some points or even negative. And no i have never pulled heads before but a lot of internet research and YouTube videos should do it. But i have replaced the manifold and risers about a year ago and they should not be giving me any problems. Yes and when i start to take the engine apart i will record everything so you guys can see if i am doing anything wrong. Yes i will look at every everything with great detail for a very detailed visual inspection!
 

achris

More fish than mountain goat
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Re: Cylinders Low In PSI ? (HELP)

Manual? And BTW, what is your engine serial number?
 

84EdH

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Re: Cylinders Low In PSI ? (HELP)

Just to throw another bone on the pile: If those high readings are legit, there most likely is water seeping into the high cylinders. obviously not so much to lock it up, but enough to push the readings up. might explain some of the variability in the readings also, if more or less water was in certain cylinders after shut down.


If the drive is off the boat, and if I understand correctly, the engine still runs, before you take the heads off, run the engine without water. (I know your precious antifreeze....put it in a couple of gallon jugs and save it if you like). you can run the engine, without the drive attached (to save the impeller), for maybe two minutes before it gets too hot. this will allow any cylinder water to be blown out. Then, redo your compression tests. I bet the high readings go away. And then your left with finding the source of the water ingestion into the block......could be bad news!
 
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achris

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Re: Cylinders Low In PSI ? (HELP)

Sorry Ed, :nono: Without cooling water the exhaust shutters and other rubber parts in the exhaust system are going to get burnt up... Do not run the engine without water, even if the drive is off...
 

84EdH

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Re: Cylinders Low In PSI ? (HELP)

In two minutes? Even 30 seconds might be enough to blow off water in a dry block. Maybe even just cranking with plugs pulled a few cycles in a dry block would do the trick? At least it would be telling if new compression numers were lower.

Also: you have best animated expression characters:joyous:
 

achris

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Re: Cylinders Low In PSI ? (HELP)

Yes, in 2 minutes. Go and start your car engine, then try and hold your hand at the exhaust pipe for 2 minutes.... See how hot that gets, and it's 12 feet from the manifold. The shutter are about 18 inches :eek:

Like my Smilies? :thumb: Thanks.
 

84EdH

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Re: Cylinders Low In PSI ? (HELP)

Take your word for it. Too cold. Boat bedded in for 4-5 months. Ed too lazy.:lol:

ok, I re-read..start my CAR engine. still, take your word for it. see above ^


Chris, when do you sleep? :eek:
 
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BigDog98

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Re: Cylinders Low In PSI ? (HELP)

Just to throw another bone on the pile: If those high readings are legit, there most likely is water seeping into the high cylinders. obviously not so much to lock it up, but enough to push the readings up. might explain some of the variability in the readings also, if more or less water was in certain cylinders after shut down.


If the drive is off the boat, and if I understand correctly, the engine still runs, before you take the heads off, run the engine without water. (I know your precious antifreeze....put it in a couple of gallon jugs and save it if you like). you can run the engine, without the drive attached (to save the impeller), for maybe two minutes before it gets too hot. this will allow any cylinder water to be blown out. Then, redo your compression tests. I bet the high readings go away. And then your left with finding the source of the water ingestion into the block......could be bad news!

Ahh good thing you mentioned it. I did run the engine without the drive and i ran the engine for about 5 mins without the water then i did the test.
 

84EdH

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Re: Cylinders Low In PSI ? (HELP)

You better put flappers and rubber exhaust sleeves on your parts to buy list.
 

achris

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Re: Cylinders Low In PSI ? (HELP)

Chris, when do you sleep? :eek:

What is this thing you call 'sleep'? :lol:

Just got back from New Zealand, where I was working night shift (midnight to midday)... My clock is so screwed up :facepalm: I sleep when I'm tired, usually about 4pm to 9pm local time.... Then come play with you lot on here... :rofl:
 

84EdH

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Re: Cylinders Low In PSI ? (HELP)

I wondered if you had become an insomniac:confused:

Glad to play antime:D
 

BigDog98

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Re: Cylinders Low In PSI ? (HELP)

Postin another video that will hopeful have you guys understand me a bit more because honestly the last video was bad.
 

banshee owner

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Re: Cylinders Low In PSI ? (HELP)

would it be to hard to get a video of the engine running idle quality and maybe exhaust. there maybe clues as to whats going on if we hear it running.

if its too much work don't worry about it
 

achris

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Re: Cylinders Low In PSI ? (HELP)

Watching the video... I'll make comments as I'm watching, so they may be a little disjointed...

1. Makes no difference between removing the heads to replace the head gaskets and removing the heads to have them worked... Exactly the same amount of work for you.
2. Your compression gauge is fine... ($40 is not a lot for good tools...)
3. Inside the tube is a SCHRADER valve. (car tyre valve)
4. Water squirting out when cranking.... You're right about that one. Another possible cause of high pressure could be carbon build-up...
5. Leave the other threads until later... It could lead to a lot of confusion with multiple threads running at the same time... Do one thing at a time and do it properly..
6. Correct about the timing marks and getting the cylinders to TDC... Firing order is 1-8-4-3-6-5-7-2
7. Rule#1 about boats and money. You will never get all the money you put into a boat back... Accountants call this a 'liability'. If you want an asset, buy a house....
8. You'll be replacing the head gaskets anyway. They are 'single use' parts.... always... Gaskets can't and should never be reused.
9. Head bolts need a 5/8" socket.
10. I suggest using a 1/2" drive set for working on these engines.
11. Get yourself a brickies wooden float and put a length of fine emery cloth along the bottom. Makes cleaning gasket surfaces easier... Same with a 1-1/2 or 2" wood chisel.
12. DO YOU HAVE THE GENUINE SERVICE-MANUAL????

Chris.....
 
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xjdriver

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Re: Cylinders Low In PSI ? (HELP)

Im wondering, what made you do the comp test in the first place? Loss inperformance? Rough idle? And why do you have such big boats? Small boats are simpler. Yes the test with the air compressor will work, what you wana do is get the cyl your testing on tdc or a little past, then when you add air the pressure will rotate the engine over to bottom dead center, to ensure your valves arnt open.
 
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