1993 150 fast strike only high idle HELP

[Tommygreeneyez]

Ok, I have hit a snafu while out on the river the tonight. The motor starts fine, but it will not go out of high idle and stay running. When it starts I advance the timing with the lever and the engine runs, doesnt sound right, and seems to run at a lower RPM than it should, and if I drop it to idle it will die, or if it doesnt, as soon as I engage the drive it dies. Ok now the funky part, it only happens if the exhaust is in the water. if I run it on land, or raise the prop out of the water it will rev up just fine, and run fine. Once I lower the prop into the water it starts lugging down and then doesnt want to run. I just changed the plugs, Champion QL77JC4's, and checked and I have spark on all 6 cylinders. I am planning on taking it to a shop tomorrow, but I would love to have some ideas as to what is wrong with it. It is getting plenty of fuel, I just replaced the fuel line. Looks like the VRO pump is working ok because it gives a good plume of white smoke when it first fires up, and on land it will fire with either the engine trimmed up or down, so I dont think the diaphragm is out on the VRO allowing it to only run whyen trimmed up. I am lost, and I am aggrevated. Please someone help.

 

[jtexas]

Re: 1993 150 fast strike only high idle HELP

you realize that it only takes a couple minutes dry running to burn up a water pump impeller......

No mystery at all about outboards that run great on land then crap out once they get backpressure on the exhaust from being in the water - it's the most common thing in the world. You've got a cylinder or two or three dropping out at idle.

If you have good spark and good compression, all that's left is fuel. Likely a clogged idle passage in one or more carbs. Also possible to see a spark on all holes outside the cylinder, but too weak to fire under pressure. A spark test at 1/2" is a better indicator.

 

[Tommygreeneyez]

Re: 1993 150 fast strike only high idle HELP

I ALWAYS run it with a set of muffs on when its not in the water. Yeah i figured it was either fule or a cylinder dropping out. I am taking it to a shop today. Thanks

 

[Tommygreeneyez]

Re: 1993 150 fast strike only high idle HELP

Well the shop found no compression on the bottom 2 cylinders on the port side. They took it apart and found the cylinder walls had some grooves in them. I asked and the tech said it was not a carbon build up problem, he said it looks like it ran lean at some point, or bad oil was put in. He also said that there is plenty of oil on the cyl walls now so he doesnt know. I bought this boat and I only have like maybe 2 hours on it running, Any ideas as to what caused this. The only thing I can think of is the guy I bought it from let the VRO resevior run out of oil for a period of time, but I dont know. They said they didnt know if they could get the grooves out by boring over .025". And said I need a new motor or power head for 3-4K. I called another shop (johnson dealer) and they looked up my model number and said it can go .040" without a problem. So the first shop is sending it out to be machined and they are rebuilding for 2000-2500. I know the VRO was working when I had it because the level was decreasing as fuel was comsumed.

 

[jtexas]

Re: 1993 150 fast strike only high idle HELP

bumping this up, to see if anybody has a theory about port side cylinders scored.

Don't see how a dry oil reservoir could cause a problem only on 1/3 of the cylinders.

 

[Tommygreeneyez]

Re: 1993 150 fast strike only high idle HELP

I picked it up from that dealer, and took it to another because they only wanted to seel me a brand new engine. no used, nothing. found out the fly wheel magnets were chewed up and i wanted a new starter, and they told me it isnt worth it just buy a brand new one for 8000. So i took it to another dealer and they sold me a used yamaha 115. runs great. but yeah I am really curious as to what would cause the port scoring only. They said the oil that was in it felt a little powdery too, so I am clueless. I would love to find out, and maybe find someone to buy the motor who would wanna do the work themself and get it runnin good for them....

 

[hoeser]

Re: 1993 150 fast strike only high idle HELP

I'm curious on "the shop's" definition of "no compression" - 0 compression to me would indicate a ring let go, not just scoring. With the rings in place, even with a scored cylinder you will still show some compression. When my upper ring let go it showed absolutely 0. Your VRO wouldn't kill only 2 cylinders... maybe a lean condition cause by dirty carbs?

 

[reeldutch]

Re: 1993 150 fast strike only high idle HELP

if the oil sticking on the cylinderwalls feels powdery that could indicate that they put 4 stroke oil in the vro tank.
4stroke oil will leave a ash residu lots of carbon .
but the vro will do this on all 6 cylinders. not pick only 2.
so check those out too.