1987 Classic 50 Throttle Issue

[Dilligaf76]

MY dad had a Bass Tracker that sat for 5-6 years. its now mine and I'm trying to get the engine running smooth. The first few trips on the water went fine and the engine ran well. The first time I actually tried to take it fishing we had a few problems the main one being it wont go to full throttle while in gear. It did great long enough to get 5 miles from the ramp. It will tach up in N and in the driveway with the muffs on but once its in the water it lets me down. This last time it wouldn't even stay running enough to get back to the ramp. Luckily it has a functioning trolling motor so we were able to get back with that. The first trip it let me down on I did find some loose bolts and screws. My dad had Alzheimers so I'm afraid he may have been tinkering with it and maybe theres a screw/bolt that has come loose?
I dont know a lot about 2stroke engines and dont really want to sink a ton of money into such an old boat. Dad was very good at this kind of thing and took great care of what he had. If i could get it reliable cheaply I'd like to keep it since I know it was maintained well.
Any help is appreciated!

 

[racerone]

Those are a wonderful / simple motor.----You are far better off $$$ wise with that motor that a new computer controlled motor that requires $100/hr dealer support !------Post the results of a compression test.----Then see if there is spark on each lead that jumps a gap of 3/8" or more.------You did install a new water pump impeller I hope.----They all---- " bark and roar " ----on a hose and that means very little.-----They will sound good running on 3 of 4 cylinders !!

 

[Dilligaf76]

I' reasonably sure I found the problem. I decided to change the fuel filter and noticed a screw under it. Started looking for its home and found this broken piece in the photo. It would explain why it wont idle and why it would only go half throttle.

racerone: I'm guessing I should start looking to replace the impeller?

 

[Dilligaf76]

[No message]

 

[huntxtrm]

Dont lose that screw and bumper. I cant find one. I had to get one at Home Depot. So, for now I have the screw with no bumper. Having some sync issues with mine right now as well. Exact same motor. 87 vlassic 50. Trying to find the right manual for it is tricky as well. Im still looking for a manual also. Found generic Seloc manuals, but it doesnt state it covers this motor.

 

[Dilligaf76]

I finally had a chance to put the boat in the water and try it out. Same issue. Its seems that it wont go to full throttle under a load. In neutral it will tach up but kinda takes its time getting there. It does great in the driveway lol. Could it be a fuel delivery issue? Timing? I'm at the end of my abilities. I ordered some carb rebuild kits and jets so i have those. The float and bowls looked clean.
What would be the next step to troubleshoot this?
All help is appreciated.

 

[emoney]

Start with the basics; compression test first and check the spark. Parts store will probably loan you a compression tester but they’re not that expensive. Sounds like the boat was sitting for a while so tell us what you did before you started it; drain the fuel, check the fuel lines? Hoping you put a heavy mix of oil in the beginning? Lots of good videos on starting an outboard that’s been sitting. Not using one is often just as bad as misusing one. If compression and spark are good, I would replace every fuel line on the boat. You can start narrowing things down by using a different portable gas tank. Rebuilding those carbs is a great first step but I would confirm compression and spark first.

 

[huntxtrm]

I' reasonably sure I found the problem. I decided to change the fuel filter and noticed a screw under it. Started looking for its home and found this broken piece in the photo. It would explain why it wont idle and why it would only go half throttle.

racerone: I'm guessing I should start looking to replace the impeller?

You did replace that bracket the screw came out of correct?

 

[huntxtrm]

And adjust it. Acording to my manual. Disconnect the throttle cable, move throttle lever to untill the max spark advance just touches the bumper. Then adjust the screw in until it just touches the throttle lever on the carb. No more, and back it off of it just a touch. If you need me too, i can try and post the page. I have the exact same motor, working on the same issues.

 

[Dilligaf76]

You did replace that bracket the screw came out of correct?

I have the new bracket and screw installed. I moved everything around while it was in the water just to see what would happen. I'm 99% sure the throttle is going wide open.

I removed the plugs and sprayed oil into the cylinders before I turned it over, replaced the fuel. The motor ran great the first couple times i took it out once I got it going. Dad was pretty good with engines and got frustrated enough to pay someone to try and get this thing running well.

I'll check the plugs and compression then start working on the fuel system. I'm a little intimidated by rebuilding the carbs myself. Not the rebuilding part, the adjustment part.

 

[Dilligaf76]

Compression test shows 70 psi on all four cylinders. I put an in-line spark tester on it and only the top two cylinders have spark. I moved some wires around to trouble shoot bad plug wires but theyre all good. I put a volt meter on what I assume is the computer and they all showed around two volts each. Theres one more set of boxes that the wires plug into and i cant seem to get a reading on the wires from them. What are those? I also found a couple wires that were just hanging around.

 

[Dilligaf76]

So using this troubleshooting guide I think the Switch Box must be bad. I'm no wizard with a multi-meter. When i put the resistance dial to 20k I get 6.64 for the stator resistance tests across blue and blue/white. Then set it to 200 and get 153.8 red and red/white. I assume this is within the specs?
I then swapped the wires coming into the switch box and fired it up. Nothing changed as far as the bottom two cylinders not having spark. The top two still had spark.
Its amazing it'll run on two cylinders.

 

[huntxtrm]

Compression test shows 70 psi on all four cylinders. I put an in-line spark tester on it and only the top two cylinders have spark. I moved some wires around to trouble shoot bad plug wires but theyre all good. I put a volt meter on what I assume is the computer and they all showed around two volts each. Theres one more set of boxes that the wires plug into and i cant seem to get a reading on the wires from them. What are those? I also found a couple wires that were just hanging around.

Im no certified boat mech, but 70psi is really low! Are you sure your comp tester is good?