Tohatsu 50Hp Project - Page 3

jeffstevens763@g · 06 December 2016, 17:23

Ok starting from the beginning there was no thermostat that would worry me because it might have overheated so the head needs checking for warp if ok then it can be put back together after clean up that also includes any water that has got into the crank case through the inlet ports when the piston is at the bottom of its stroke. There should be a drain somewhere or it would mean taking the carbs off and read valves to get in there the reeds need checking for corrosion anyway for it to run correctly (sticking reeds) it's only my opinion and I am not an expert but I would say you have quite a bit of water in there which needs drying out and a good spray of fogging oil on all parts.its worth the work in the long run as the engine has had a bit of rough treatment re the spark plug threads and thermostat might as well get it sorted in a one.there might be something on YouTube re getting into thr crankcase.

Cheers

watersidemat · 10 December 2016, 15:09

OK so work done today:

thermostat tested and is working so that's good news.

reed block taken off and that's in really good condition so i'm very happy there's nothing to do there!

taking that off game let me have a look into the crank case, i sprayed oil into that and turned the engine until the water was displaced and it was just oil coming up out the cylinders, the oil should just burn off eventually? also the crank is turning much easier now!

Cylinder head isn't warped so that's back on all with new gaskets so i hope that will stay sealed up now and third time's the charm!

waiting on 3 new gaskets for the air intake manifold bit to put the reed block back in, re fit the carbs and sort out the fuel line and hopefully its ready for the water in time for Christmas!

jeffstevens763@g · 10 December 2016, 16:52

Fingers crossed it will be ok just for info and future help there's a guy on YouTube dangar marine loads of stuff balancing carbs, strip downs, changing reeds the lot worth looking at.

Cheers

watersidemat · 10 December 2016, 17:11

Quote:

Originally Posted by jeffstevens763@g

Fingers crossed it will be ok just for info and future help there's a guy on YouTube dangar marine loads of stuff balancing carbs, strip downs, changing reeds the lot worth looking at.

Cheers

Been watching all of those videos, very useful.

watersidemat · 20 December 2016, 15:38

https://www.youtube.com/watch?v=Xe62nPJa6dc

Well it's running, can't see any evidence of water leaking into the cylinders like i had before.
hopefully that's it now in a usable state!

The only thing this time is im getting condensation on the top of the carburetor but that could be the temperature, its pretty cold today.
also there's like a dry ice residue on the back butterfly valve inside the carbie.
it's like a dry ice solid oily residue, might be fuel related or to do with the cold?

i have tried to adjust the fuel mixture screws on the carburetors but cant seem to get a change in how it runs at all so i have set them to the service manual standard 2-1/2 turns outward, carbs are cleaned so this should be fine for now.

really i just want to get it on the water, see how it runs in gear and higher revs, see if it goes!

jeffstevens763@g · 20 December 2016, 17:42

Lot of moisture in the air, cold and will have a slight wind chill factor drawing air into the carbs leaving residue, worth looking at carb set up on dangar or similar to check set up but she sounds nice though bet your itching for a blast

watersidemat · 20 December 2016, 17:43

Taking it for a run up the river tomorrow, see what happens!

jeffstevens763@g · 20 December 2016, 17:45

Quote:

Originally Posted by watersidemat

Taking it for a run up the river tomorrow, see what happens!

Fingers crossed enjoy

lukewhiting · 20 December 2016, 17:50

I get condensation on mine, nothing to worry about!

Good luck!

watersidemat · 21 December 2016, 13:37

Success! she runs well.
accelerates nice and sounds happy enough idling and through the rev range and picks up some speed for an old gal!
didn't take any readings today, didn't want to jinx it just wanted to see if it could travel in a forward direction.
only thing is when it's at WOT the revs would die off and id have to throttle back and work back up the rev range, it would run at WOT for about 50 meters or so at a time sometimes longer but eventually it would decelerate, holding it at WOT from here it doesn't pick up again, you have to throttle back and come up again.
keep it a twist off WOT and it runs fine, and its fast enough!

shouldn't be an issue on the sea because when are you ever at WOT for a long time when there's a bit of swell, but on the river, flat calm and you can pin it WOT it dies off abit, any quick fixes because i'm not opening it up again to fix it its not that much of a big deal. possibly rev limiter?

Anyway it works and i have a new toy!

lukewhiting · 21 December 2016, 17:32

Quote:

Originally Posted by watersidemat

Success! she runs well.
accelerates nice and sounds happy enough idling and through the rev range and picks up some speed for an old gal!
didn't take any readings today, didn't want to jinx it just wanted to see if it could travel in a forward direction.
only thing is when it's at WOT the revs would die off and id have to throttle back and work back up the rev range, it would run at WOT for about 50 meters or so at a time sometimes longer but eventually it would decelerate, holding it at WOT from here it doesn't pick up again, you have to throttle back and come up again.
keep it a twist off WOT and it runs fine, and its fast enough!

shouldn't be an issue on the sea because when are you ever at WOT for a long time when there's a bit of swell, but on the river, flat calm and you can pin it WOT it dies off abit, any quick fixes because i'm not opening it up again to fix it its not that much of a big deal. possibly rev limiter?

Anyway it works and i have a new toy!

Trust me when your used to it your be pinning that throttle from the start!

Sounds like coils to me?
Does it ever stall?

watersidemat · 21 December 2016, 17:51

Never stalled, coils are the nacaru ones, could be my dodgy wiring!

Roflhat · 22 December 2016, 18:19

Double check the earths on them, maybe worth linking all the earths together too.
Doesn't sound like rev limiter, it just bounces off wot but doesn't drop to idle, it's at 5850rpm.
What fuel mixture are you running?

jeffstevens763@g · 22 December 2016, 19:11

Fuel pump not keeping up at WOT.?

watersidemat · 22 December 2016, 20:54

Quote:

Originally Posted by Roflhat

Double check the earths on them, maybe worth linking all the earths together too.
Doesn't sound like rev limiter, it just bounces off wot but doesn't drop to idle, it's at 5850rpm.
What fuel mixture are you running?

All earth to the same point?

50:1 mix

watersidemat · 22 December 2016, 20:57

Quote:

Originally Posted by jeffstevens763@g

Fuel pump not keeping up at WOT.?

Would have thought it if it wasn't for today. I'm back to square one.

Took it out today and got maybe a ten second run at full speed then it would slow down again, the difference today was the power would rise and fall randomly throughout the throttle range and got gradually worse until all it could do was idle around at slow speed, increasing throttle caused it to stall.

I'm going to try really wiring the coils and clean the plugs, see if it's a ignition coils. Mechanically it sounds ok

jeffstevens763@g · 23 December 2016, 07:37

maybe the pump has totally failed try pumping the primer builb see if that makes a difference keeping the float chambers full.

lukewhiting · 23 December 2016, 07:48

You can try removing the fuel pipe on the top carb when it's running so you can see the fuel flow. Plenty should come out!

I rebuild my fuel pump, cost about £40

watersidemat · 23 December 2016, 10:00

I'll test the fuel pump but the primer bulb stays firm through the the run, would that not go soft or be able to squeeze more fuel into the engine?. It's worth a test. Thanks again

jeffstevens763@g · 23 December 2016, 12:22

yes the bulb would go soft if fuel was used up unless there is a blockage or the bulb valves are not working but you should be able to check that by taking the fuel lead off as luke has said. some bulbs go really hard with age too.prime up and see if the float chambers are full by opening the drain screws other than that it looks like a carboretter overhall and set up back to dangar marine videos.