Compression problem? What next? UPDATE

[wilde1j]

Re: Compression problem? What next? UPDATE

If you've been running in a barrel, it will smoke a lot more than on a boat. Let it rip on a boat. You torqued the head bolts, right? And you will need to retorque after about ten hours of run time.

 

[art25]

Re: Compression problem? What next? UPDATE

you still have a major compression problem. compression on that motor should be a hundred pounds or better. i did a little research for you to confirm this. while you had the head off did you notice any scoring on the cylinder wall? any off color patches on the wall? if you did not check for it i would. its worth it for the price of another gasket cause if you really score it from "running the snot out of it" your looking at having to get a new head of having it resleaved, compared to just a hone and a set of rings if its not that bad.

 

[bob1340]

Re: Compression problem? What next? UPDATE

If you've been running in a barrel, it will smoke a lot more than on a boat. Let it rip on a boat. You torqued the head bolts, right? And you will need to retorque after about ten hours of run time.

Of course I torqued them. I think the previous owner put them on with a crescent wrench before. I had to build a crowfoot wrench to fit on my 3/8" inch pound torque wrench to get the bottom two bolts so I used it on all ten.

Hopefully in the next 2-3 days we can get it out to the lake and see what it does. I figure I will re-torque the bolts after the first outing.

 

[bob1340]

Re: Compression problem? What next? UPDATE

you still have a major compression problem. compression on that motor should be a hundred pounds or better. i did a little research for you to confirm this. while you had the head off did you notice any scoring on the cylinder wall? any off color patches on the wall? if you did not check for it i would. its worth it for the price of another gasket cause if you really score it from "running the snot out of it" your looking at having to get a new head of having it resleaved, compared to just a hone and a set of rings if its not that bad.

Zero scoring on the sleeves, I checked it well. No discoloration either.

EDIT: The tech guy at the local shop said it is common to have low compression on a motor like this that has not been run in years and years. This one sat idle for almost 20 years, 15 at least. He suggested the decarb thing and running it under load and many times that re-seats the rings.

 

[art25]

Re: Compression problem? What next? UPDATE

if there is no scoring or discoloration were making progress haha. but like i said that thing should be near at least 100 pounds in each cylinder. since there is no scoring though i agree with the others about running it and seeing what happens. if it does not gain pressure and clear up i would check the gasket again since they are cheap enough and look for the telltale black blowout marks again. if no blowout marks then odds are your gonna need a set of rings. if there are marks again i would recomend taking the head to a shop and having them mill it. hope she comes back on the lake though. good luck!

 

[boobie]

Re: Compression problem? What next? UPDATE

You mean you still haven't "ran the snot out of it " on the lake yet ? Shame!

 

[bob1340]

Re: Compression problem? What next? UPDATE

hope she comes back on the lake though. good luck!

I hope for that as well. I am not opposed to re-ringing it though, I love working on stuff.

You mean you still haven't "ran the snot out of it " on the lake yet ? Shame!

Hopefully in the next couple days. This is my kid's boat. He inherited it from his wife's grandfather. He still hasn't got it tagged yet. I'm pretty sure he has the pink slip or whatever papers boats use, but it was last registered in 1984!

 

[bob1340]

Re: Compression problem? What next? UPDATE

Well we put her in the lake today, first time in 24 years this boat got wet! Valco 14" aluminum. The motor ran smooth, but it would not power up correctly. Acted like it was at 1/2 throttle. Next outing I will try the seafoam again per instructions. If that does not unstick the rings I'll go into the motor and re-ring it.

 

[boobie]

Re: Compression problem? What next? UPDATE

My only other question would be, is it running on both cylinders? Did you do a cyl drop test on it when you had it under power?

 

[bob1340]

Re: Compression problem? What next? UPDATE

My only other question would be, is it running on both cylinders? Did you do a cyl drop test on it when you had it under power?

Sure didn't. But it sounds pretty smooth so I'd say they are both running.

 

[jonesg]

Re: Compression problem? What next? UPDATE

As I understand it, you will not see 100psi with a pull start unless you have a bionic arm pulling the rope for you.

Mine was way down on compression, had a mechanic come out and he sprayed deep creep (seafoam aerosol) in the cyl's, left it for 30 minutes and then ran it to flush it out, we could see the carbon coming out in the prop water (on hose). Compression went up, so we did it again and added some to the fuel, compression ended up around 85psi, ok for a V6.
The deep creep will not harm the metal, it will eat the carbon up though.
You should be able to get the rings unstuck.

 

[bob1340]

Re: Compression problem? What next? UPDATE

As I understand it, you will not see 100psi with a pull start unless you have a bionic arm pulling the rope for you.

Mine was way down on compression, had a mechanic come out and he sprayed deep creep (seafoam aerosol) in the cyl's, left it for 30 minutes and then ran it to flush it out, we could see the carbon coming out in the prop water (on hose). Compression went up, so we did it again and added some to the fuel, compression ended up around 85psi, ok for a V6.
The deep creep will not harm the metal, it will eat the carbon up though.
You should be able to get the rings unstuck.

I want to do that, but I have not been able to find the deep creep! I can find the regular pint cans of the seafoam, but not the deep creep. Where are you buying it? Are you spraying it down the plug hole on a warm/hot motor or just putting it in cold?

 

[boobie]

Re: Compression problem? What next? UPDATE

A mtr running on 1 cyl will sound very smooth yet you will have no power. That's the reason for a cyl drop test. IE: shorting out or pulling off one plug wire at a time to see if the cyl is firing. If you notice a drop that cyl is firing.

 

[bob1340]

Re: Compression problem? What next? UPDATE

A mtr running on 1 cyl will sound very smooth yet you will have no power. That's the reason for a cyl drop test. IE: shorting out or pulling off one plug wire at a time to see if the cyl is firing. If you notice a drop that cyl is firing.

thanks. Iam gonna try that once I get the chance. Everything but the plug wires And the flywheel are new in the ignition department. I will check each cable via a spark tester. I just got a real nice one at Pep Boys for $7.00 today. No Deep Creep stuff though.

 

[clemsonfor]

Re: Compression problem? What next? UPDATE

I want to do that, but I have not been able to find the deep creep! I can find the regular pint cans of the seafoam, but not the deep creep. Where are you buying it? Are you spraying it down the plug hole on a warm/hot motor or just putting it in cold?

A couple things. Hope your not trying the high revs in a barrel. It can run away and blow up. A twin cyl can run well on one cyl and sound smooth, it turns into a single cyl motor like the small ones. Deep creep is the same as the regular seafoam. Buy a cheap $1 spray bottle at the dollar store and fill it with a couple ounces of seafoam and unscrew plug and spray into hole and into throat of carbs and pull the rope slowly to cycle the pistons and spay a little more and let sit. Put plugs back and in 20 mins start it and stand upwind. Like others said i dont think you will ever see 110 psi from a rope pull it takes a bunch of piston strokes to peak it out, you spin a car or electric over for a second or two to get a reading. Oh dont pay alot for the spray bottle, the one i got had the seals eaten by the seafoam or maybe the mix fuel i put in later so i threw it out after.