Vro Pump

[funpilot]

Hi Phill
Go to the FAQ httpwwwiboatscombbboardbbBoardcgiaviewforumfid36 http://www.iboats.com/bbboard/bbBoard.cgi?a=viewforum;fid=36
and read about VRO.

Basically, it can't burn up single cylinder. A carb can do that, or the wrong sparkplug, but a VRO mixes fuel and oil and delivers the same mix to all carbs. You don't say what motor it is on, or if in the process of using the motor you used some of the oil in the reservoir, but as a rule, when I do a rebuild or change out VRO components I run a 50:1 mix in my fuel until I know the VRO is functioning again.

good luck,
fp

 

[seahorse5]

Re: Vro Pump

this link has a picture and bit better explanation of the "VRO" pump.

http://continuouswave.com/whaler/reference/VRO.html

It is true, the "VRO" can't burn up just one cylinder.

Let me ask a question, if you mixed your own oil and gas toghether, and one cylinder failed, what would you think of your mechanic if he said that you did not mix any oil in the gas, and that's why the cylinder was damaged?

 

[Phillip]

Re: Vro Pump

this is a tough one huh??!?!?!?!??!?!??!!??
please ill accept ANY thoughts from anyone just another idea to kick around while im overhauling this engine for the second time

 

[funpilot]

Re: Vro Pump

Phill,

As far as I can figure, you've got about three threads going on this post, all for the rebuild and VRO problems. Let's stick to this one thread here.

I'm not an expert, but last month I rebuilt my 1990 90hp because of stuck rings wrecked number one cylinder. In my case, the exhaust cover gaskets failed causing the starboard bank of cylinders to overheat.

After a rebuild, as I said, you should run 50:1 premix along with your VRO system to berak in the engine and verify that the VRO is operating. In my case, I was careful to make sure all the parts were where they belonged before I started the engine (in another thread you say you left your pulse limiter for the VRO off the engine when you started the engine the first time). The other thing you have to do after a rebuild is do not ignore warnings. Since I'm not an expert, I don't know what your warning horns are for on your motor, but as a rule, shutting down and finding out what the problem is and getting towed back beats a second engine rebuild any time.

Things that could cause a cylinder to burn up would include a head full of knicks and dents from a previous piston and ring breaking up; bad water flow in an engine due to stuck thermostats and improperly installed gaskets; gunk under the head covers (those little plates which are screwed to the top of the cylinder heads); head gaskets installed backwards or upside down; a badly done link and synch for the carb, throttle and timing advanced linkages; advanced timing; wrong spark plugs; warped engine parts allowing water to escape from cooling passages.

Some of these things would take several hours to cook a cylinder, some of these things would go faster. Did you reset your timing properly? Did you replace or at least test your thermostats? When the horn went off could you touch your heads for several seconds to verify they were getting cooling, or were they too hot to touch? Which cylinder let go, the starboard side runs hotter.

The forum is undergoing updates and is slow. You will have to be patient and let people get to you.

good luck,
fp

 

[Phillip]

Re: Vro Pump

Phill,

As far as I can figure, you've got about three threads going on this post, all for the rebuild and VRO problems. Let's stick to this one thread here.

I'm not an expert, but last month I rebuilt my 1990 90hp because of stuck rings wrecked number one cylinder. In my case, the exhaust cover gaskets failed causing the starboard bank of cylinders to overheat.

After a rebuild, as I said, you should run 50:1 premix along with your VRO system to berak in the engine and verify that the VRO is operating. In my case, I was careful to make sure all the parts were where they belonged before I started the engine (in another thread you say you left your pulse limiter for the VRO off the engine when you started the engine the first time). The other thing you have to do after a rebuild is do not ignore warnings. Since I'm not an expert, I don't know what your warning horns are for on your motor, but as a rule, shutting down and finding out what the problem is and getting towed back beats a second engine rebuild any time.

Things that could cause a cylinder to burn up would include a head full of knicks and dents from a previous piston and ring breaking up; bad water flow in an engine due to stuck thermostats and improperly installed gaskets; gunk under the head covers (those little plates which are screwed to the top of the cylinder heads); head gaskets installed backwards or upside down; a badly done link and synch for the carb, throttle and timing advanced linkages; advanced timing; wrong spark plugs; warped engine parts allowing water to escape from cooling passages.

Some of these things would take several hours to cook a cylinder, some of these things would go faster. Did you reset your timing properly? Did you replace or at least test your thermostats? When the horn went off could you touch your heads for several seconds to verify they were getting cooling, or were they too hot to touch? Which cylinder let go, the starboard side runs hotter.

The forum is undergoing updates and is slow. You will have to be patient and let people get to you.

good luck,
fp

ill do my best to explain things a little better.
when we overhauled the engine the first time we had all four pistons bored out .030 over and oversize pistons and rings. The thermostats were brand new. the starboard head gasket where the piston burnt up was installed upside down.The carbs were rebuilt and synchronized by a mechanic. I still have no idea how to time a two stroke engine. and the heads were also milled down, so they werent warped. The piston locked into place not too long after the warning horn went off.

 

[funpilot]

Re: Vro Pump

The heads have numbers on them indicating which cylinder is which. Number one is the top on the starboard side, number two is the the top on the port side, number three is the bottom on the starboard side and four is bottom of the port side. Which one is stuck? Starboard tends to run hotter and lose cooling easier than port. When you restart this thing, you should be able to idle it with your hand on the heads for short periods of time before you feel like it is too hot to touch.

I've not seen pistons larger than .030 over for these motors, so I hope you can simply hone this hole and get a new set of rings if your piston is still good.

Do you mean to say that the head gasket was installed upside down before you rebuilt the engine, or that you found it that way when you got the locked up piston just now? I can't see your motor but I'm leaning to a cooling failure since you had a warning horn. If your mechanic synched your carbs, ask him if he timed the engine as well.

I wish the search feature would allow me to point you to timing your engine via what is known on iboats as the "Joe Reeves" method, but I can't so I'll just describe it.

You need to be able to turn your engine over with the spark plugs out and the throttle position in wide open throttle. To do this I ususally disconnect the throttle cable from the engine and advance the throttle bracket on the engine manually. The plug wires should each be attached to a spark plug tester gapped at 7/16th of an inch. I use a homemade one, but sometimes you can find them at a store. Using a spark tester prevents the coils from loading up and failing. With the throttle bracket advanced, and the timing mechanism advanced along with it (it goes to the moving piece up under the flywheel) you crank the engine on the battery, and measure the timing on the flywheel with the timing light. If your engine says to use 28 degrees BTDC you time it at four degrees retarded (24 in this case) as the engine senses that it isn't running at the proper RPM for WOT and retards the timing four degrees to keep the engine safe. You reinstall the spark plugs and the throttle cable and run the engine (at the lake) where WOT will be close to the proper setting.

good luck,
fp

 

[Phillip]

Re: Vro Pump

Well thanks for the information. i have the engine torn apart now and i took the block to my cousin Dave who is an ASE master certified mechanic and told him about what happened. you see when i overhauled the engine i somehow installed the head gasket upside down which i noticed after i took the compression test and started unbolting the head so apparently i had water leaking into my cylinders which burnt them up rather quickly. oh and the number one and three pistons are burnt up i didnt think the number 3 was until i took it out, and yes your right .030 is the max it can be bored so were going to see if we can take some muratic acid into the cylinder wall to get the aluminum splatter out of the cylinder and then hone it and see if we can still use it. So basically im beating myself up now for installing a head gasket in upside down and for ignoring warning horns but at least ive learned a little bit and thanks a lot for the timing info. The book didnt do much but confuse me on this issue. Since this is the second time ive had this engine apart I think ill take my time and make sure all the gaskets are installed properly.

 

[Phillip]

Re: Vro Pump

Thanks a lot really i appreciate the information!

 

[funpilot]

Re: Vro Pump

Phillip,

Thanks for taking the time to give us some feedback as to what you believe is wrong with your motor, and what you have found out so far. I hope the muratic acid does the trick, and that you can have a second chance with your motor. I do believe that you have saved someone else some grief by posting your information and questions here.

Good luck,
fp