Tohatsu 50Hp Project

[jeffstevens763@g]

It says it fits so should be ok

[watersidemat]

Just so you know i hate the sound of my own voice so this video is far from my favorite but hopefully it will make more sense than my text posts! i did it in one take though so be nice!

A video of today's run!

https://www.youtube.com/watch?v=8_C-_iSmgZs

if you take the time to watch thank you very much!

[Roflhat]

Check if the throttle flaps are opening fully, but I would also check the coils, see if there's a spark at each of the plugs and if they're fouling. Mine would foul and cause it to run just like that, quite easy to confuse with a fuel issue I've found

[lukewhiting]

I had the same issue with mine, I changed the plugs and rebuilt the carbs which made no difference.

Check your filters are clean. I would buy the parts to rebuild the fuel pump.

Only a 30second job to do and costs about £40.

Sounds like your idles too low also

[watersidemat]

Originally Posted by Roflhat

Check if the throttle flaps are opening fully, but I would also check the coils, see if there's a spark at each of the plugs and if they're fouling. Mine would foul and cause it to run just like that, quite easy to confuse with a fuel issue I've found

I have seen the flaps open fully and close while running on the muffin both in neutral and in gear. Probably not advisable but whatever! When in gear on the water would something stop them from opening or would they behave in the same way? I can run up.and down the river with the cowling off to see if they do.

Each plug gives a visible spark, I am going to change the plugs, the plugs were new when I started this project but they have been through the mill such as after the leaking head gasket incident so maybe they need changing. But saying that the boat did want to reach top end at the end of that video.

[watersidemat]

Originally Posted by lukewhiting

I had the same issue with mine, I changed the plugs and rebuilt the carbs which made no difference.

Check your filters are clean. I would buy the parts to rebuild the fuel pump.

Only a 30second job to do and costs about £40.

Sounds like your idles too low also

The filter is clean and I have an external filter too. I'll get a rebuild kit anyway but I've not done anything much different to it and the boat has gone very fast about 35 knots so I can't work out why it's dropped.and stopped hitting the higher revs!?

[watersidemat]

Could it be getting too much fuel. I went out with a full 20l tank and on 45 minutes of running I was down to about 1/4 a tank. Is it really that thirsty or is there fuel going to waste there.

[jeffstevens763@g]

I have listened to you video a few times I think it's miss firing I would check your coils you said you had wet plugs after running that shouldn't happen it's not burning all the fuel at WOT. Have you checked you have the correct plugs with the manual it makes a bid difference if thier wrong.once you have the spark sorted you can look at the carbs and setting them up

[watersidemat]

Correct model of plugs are in use. I Intend to buy some new ones Monday and try again.

[jeffstevens763@g]

Originally Posted by watersidemat

Correct model of plugs are in use. I Intend to buy some new ones Monday and try again.

Check your coils before you run it, shows you how on dangar marine I think it's down on one cylinder so your not getting full revs wasting fuel that's why your using a lot of fuel with the throttle wide open hence wet plugs.

[watersidemat]

Originally Posted by jeffstevens763@g

Check your coils before you run it, shows you how on dangar marine I think it's down on one cylinder so your not getting full revs wasting fuel that's why your using a lot of fuel with the throttle wide open hence wet plugs.

I'm watching that video right now! Next door neighbour has a multimeter and I might be able to find a spark plug spark distance measuring thing in town from the motor factors shop. I wired those coils in myself so that might be something to look into but the boat has gone at WOT before so I'm really stumped.

[jeffstevens763@g]

The wire on the coils are only covered in a shlac varnish and it breaks down over time it might have worked initially but now shorted but the test will prove that.also when you wired up did you clean all that grease away from the connections because that would cause a high resistance and cause problems.
how old is the engine?

[watersidemat]

No idea how old the engine is. Wouldn't like to guess. The ignition coils are new nakuru ones with new HT leads. I'm going to re wire them regardless with new wire. There is no grease around the connectors.

[jeffstevens763@g]

Process of elimination I'm afraid one bad connection all needs even new coils/ leads/caps could be duff worth checking you could ask danger stu a question he replyed to me sharpish give him your symptoms you never know he might know exactly your problem
Once the Sparks sorted it's got to be fuel related could be a slight vaccume leak that's covered in his carb set up.

[watersidemat]

Might have to buy his t-shirt and send him a message when I've exhausted all other avenues!

[lukewhiting]

Just for comparison here's a video of mine on tick over.

https://youtu.be/mf7dngMnhNM

I've had the same issues in the past as you. The boat would barely plane. I changed the plugs, renewed and reset the carbs, cleaned filters and renewed the fuel pump. It now runs sweet as anything.

[watersidemat]

Thanks for taking the time to post that. Plan of attack is going to be:
Rebuild fuel pump
Re do the wiring on the ignition coils
Test the coils and HT leads with a multimeter and
Check the spark jumps 11mm as per the service manual
New plugs and then tune/adjust the carbs to increase the idle. Failing that I'll stick a mast in it and go back to sailing!

[Roflhat]

The age of the engine should be on the lower cowling of the engine. I would wire all the coil earths together, that way even if there are 2 bad earths it will run. We just didn't this with my mates tohatsu 50 to be safe, also cleaned up and the connections.

[watersidemat]

Went for a play around with the engine today. Don't have any new parts so couldn't do much but I did take the air box at the front of the carbs off and found this green gunk sat in the openings of all three. Could this be the problem.?

[lukewhiting]

Hard to tell what it is from the photos. Fuel oil and water mix?