Speaking of Johnsons.....

TinBoats.net

Help Support TinBoats.net:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

nomowork

Well-known member
Joined
May 20, 2011
Messages
1,133
Reaction score
0
Location
The wacky west coast
I thought I'd start a new thread about my 48 special and the lack of telltale stream.

I dropped the lower unit today. It's getting easier every time! :roll: I thought I lost the shift rod grommet while pulling the lower unit down. It wasn't anywhere to be seen. I remove the port side housing to make things easier. I looked high and low and couldn't find that thing. Eventually while looking up the intake tube of the water pump, I saw the grommet stuck inside of the shift rod tube! Whew, I thought aliens were visiting me or something.

Anyway, I opened the impeller housing and it looked normal, no play in the impeller. So, I tried shooting water in the intake water tube and shazam, nothing coming out of the telltale hole. I pulled the thermostat out and no water coming out there either. String trimmer line to the rescue along with gobs of WD40. Nothing really came out but water starting flowing again when I put the hose to it so, it's time for the compressor tomorrow!

I still have to deal with the bad idle. The carbs were just rebuilt and floats replaced/adjusted along with new needle valves so now it starts up easily enough. Maybe I'll try new plugs tomorrow.

BTW, the compression in both cylinders are the same at 120 lbs.

Not that I don't have any faith in this motor, but have been pricing new ones. I'm too old to tinker with junk. I'm not getting any younger. :mrgreen:
 
On the left side of the motor there is a flat plate. (water box) Pull it off there a good chance it has something stuck in it. I'd check that before I'd try compressed air. Compresions a little low but it's good that it's even on both cylinders. Might need a new set of reeds. The reeds will become warped or the cages will get inperfections so the reeds don't close. I'd buy a set of reeds from Chris Carson Marine, should be around $50 for your motor. He's awsome to deal with and he makes a great set of reeds. I'd make sure to lap the reed cages too to make sure they're flat. Reeds not sealing up will make a diffrence in idle and start up. That's what I'd do.
Hope this helps.
 
I changed the plugs today and it fired up and idled great! I was even able to put some throttle to it without it hesitating and stumbling like usual.

The pee stream was very weak but it idled great. I watched as the pee stream slowed to a trickle then the over heat alarm went off. Then I noticed that there was smoke coming out of the pee hole! :shock: I pulled the head off and the head gasket was toast. There was a big crack in the gasket where the uptake water tube hits the head at the bottom. I'm guessing that the cylinder pressure overwhelmed the water pump pressure via the cracked gasket. The gasket had breaks is several places!

I went through this on another Evinrude before. The saga continues.
 
. I'd pop the side cover off the water box and check it out. You might have some kinda build up or something in it. Have you replaced the water pump impeller in a while?
Glad you got the idle problem figured out.
Did you try the compressed air thing. That might have cracked the head gasket. Did it flood the cylinder?
 
Just added pics of gasket.

The second picture shows lower part of head gasket (right side of picture) with a big bulge and a crack. There was a solid mass of sediment under that bulge. I believe the uptake tube from the impeller feeds from that area then up the side of the cylinder water passages to the port side of the thermostat housing then as you mention to the "box area" where the pee hole tube starts at.

I'm doing things one step at a time and just ordered the head gasket tonight. I borrow that motto of don't fix it if it isn't broken. :mrgreen:
 
The water comes up the pickup enter the box then goes it starts pumping through the head once the thermostat opens up then water exits through one hole inside the mid sectiona and another throught the pee tube. I'd say the build up was your problem or at least some of it. might have some more sediment built up but I'd make sure water is flowing good with a water hose before I'd bother with sarting the motor. theromstat doesn't need to be opened up for these motors to pee.
 
Installed new head gasket today. Compression is still the same at 120 on both cylinders. :(

The worst part, still no tell tale stream so opened up the side plate and the passages look clean, no build up of anything, so tomorrow I will pull the lower unit once again to check.

I think I'm getting closer to a re-power!
 
I'd drop the lower unit and use a water hose put straight up to the pickup tube. if water doesn't come out the pee tube then you've got a clog some where in between there. your lower unit might have something stopping it from drawing water in. You might have somehting stuck rihgt in the elbow from the pee tube. I've had that happen to me the other day. Is the gasket or grommet or whatever it is still good that goes in between the water pump and the pick up tube?
I don't think your head gasket actaully blew to let compression out. The little metal rings are what seal the compresion in the cylinder and what keep s the water out of it.
 
Pulled the lower unit and shot water up the uptake tube. Nothing coming out of the side plate near the pee hole so worked some string trimmer line down the hole and worked a clothes hanger wire up from the bottom. After many attempts and encouraging four lettered words I was able to shoot water up the pipe and out of the side plate area.

Not having a new gasket, I used some Form-A-Gasket sealant to install the side plate and will let it cure for a couple of days then try to shoot water up the pipe again.
 
Shot some water up the pipe today with the garden hose and it looked okay, not great, but okay, so installed lower unit. No pee. Now I'm thinking the tube has a leak in it so the pump cannot push the water up the pipe like a garden hose can.

The motor is also smoking badly where the drive shaft goes into the lower unit so........................it's time to REPOWER! Hope the stock market gains in the next few days so I can dip into my retirement fun money! :mrgreen:
 
Re-powered today with a used 40hp Mercury outboard. I've never had a Mercury outboard before, but wow this thing sounds awesome! It brought back memories of my hot rod days! I know it's used and I know it's "buyer beware" but did I mention the sound? It was kind of expensive but not nearly as much as a brand new 50hp Evinrude. Thanks to the guys and gals at John's Custom Marine for all the help to switch the motors over! Changed over the motor, the controls, steering and related gear in just under four hours! This I don't mind paying for!
 

Latest posts

Top