Loss of power, won't plane

[racerone]

I see damage on that impeller !!

 

[Beakster]

Ok hooked back up with new muffs and I managed to get it started and I have water from the tell tale, so muffs were the problem.

The motor should be fine if it was only a minute. The impeller should be replaced. Even though it was lubed up it could have burned and hardened the tips. You come to far to take that chance.

Thanks, this makes me feel better. I have a video I made and it was indeed just a minute, with no load on the prop.

I compared the new impeller with the old one I took out. The old one only had 1 season on it and probably didn't need replacing. When compared with the new one the new one's fins are far less curled in, so it seems that the new one is still better than the old one. Also given the fact I can see water coming from the tell tale now I think it's pumping ok but with that said... I've just ordered a new impeller so should have it Sunday and I'm hoping to take it out on the lake on Monday, so there is time.

In the mean time, I just did a compression test and got 120psi even on all cylinders. Is that what I should be getting on a 100hp?

I seem to be having trouble starting it and keeping it running. Seems like its firing on all cylinders, and I have compression so I'm suspecting a fuel issue.

I was able to start it with the fast idle lever all the way up and it ran for maybe 20 seconds and the engine speed started getting very high, so I lowered the lever a bit, and it ran rough and stalled. Then it seemed impossible to restart. The engine would spin and I'd get the odd chug out of it but it didnt want to fire. I'm wondering if maybe I'm flooding it. Fuel is definitely getting to the cylinders as I could smell it on the plugs when I pulled them. Looking for any suggestions here, I assume I should be able to get it to start and idle fairly well.

Currently running a 25:1 mix of 91 ethanol free fuel + castrol 2 stroke oil.

Can someone suggest a starting procedure from both warm and cold. This engine has the primer solenoid. I've never sure what to do with the fast idle lever... should it always be up when starting?

Thanks

 

[Beakster]

Sorry for turning this thread into a monologue . I figure I'll rebuild the carbs, install a new fuel pump and replace all the primer and recirculation hoses. Those old hoses are very hard now so I suspect they may be leaking.

 

[tphoyt]

Carb rebuild would be a great plan. If the pump
is oem rebuild it rather than replace. You’re not going to be able to do any fine tuning of the muffs. You need to be in the water for best results or a very large test tank which most don’t have access to.

 

[racerone]

Not inspecting carburetors on a rebuilt motor is a mistake.----Torqued the flywheel ?----Checked the flywheel key ?

 

[Beakster]

Not inspecting carburetors on a rebuilt motor is a mistake.----Torqued the flywheel ?----Checked the flywheel key ?

Trying to minimise what I mess with as those things are likely to be a source of problems. Idea was power head first.

How would the motor behave if you tried to start it in gear? Would that make it significantly harder to start? Right now it's at the point where you try to start, it fires once, starter disengages, and it stops. I think I need to adjust the control cables so likely it was in gear when I've been trying to start it.

 

[racerone]

You need to make sure everything is in order.----One plugged main jet and you could be doing the job over again.----After this epic struggle I doubt you want to do that.----Good luck with it.

 

[Beakster]

Getting ready to attach lower unit with a new Impeller and the upper exhaust gasket has split. I'm epoxying it back together as a new one will take a week to arrive and cost me $50.

Manual says apply adhesive M to lower unit and exhaust housing mating surfaces. Seems it was previously installed dry and none of the videos of water pump replacement I've seen have suggested doing this.

Do others do this? What sealant do you use?

 

[Faztbullet]

No sealer needed

 

[Beakster]

Rapidly losing patience here. Everything is back together again, new fuel pump, carbs rebuilt, new Impeller. Same problem as before.

She fires for a few seconds on the first try and then cuts out. Each subsequent attempt yields worse results. It spins and I get maybe one fire and a whisp of smoke. So I know I have compression fuel and ignition. What's going wrong?

 

[Beakster]

Rapidly losing patience here. Everything is back together again, new fuel pump, carbs rebuilt, new Impeller. Same problem as before.

She fires for a few seconds on the first try and then cuts out. Each subsequent attempt yields worse results. It spins and I get maybe one fire and a whisp of smoke. So I know I have compression fuel and ignition. What's going wrong?

Wondering if the minute running without water because of the dodgy muffs has damaged my new crankshaft seals and the reason I can't start her now is a lack of crankcase pressure/vacuum.

On that first start everything fired up easily and ran for a minute before I realised there was no water coming out of the tell tale. Now I cant get more than a couple of seconds of running. If that's the case I think I'm going to have to abandon the project and take it as an expensive lesson. No money or time left to continue.

 

[tphoyt]

Have you had any kind of backfire or kick back?
If so check the flywheel key. They can shear.
Did you torque the flywheel to spec?

 

[Beakster]

Not inspecting carburetors on a rebuilt motor is a mistake.----Torqued the flywheel ?----Checked the flywheel key ?

You called it first, tphoyt also called, I just checked and you're right. In my haste to check things are working I hadn't torque it properly and hence its been reduced to metal filings.

Seems like a cheap fix I just need another key?

This makes me happy though, I figured it must be some sort of timing issue. Are these keys generic in any way? Could I grab one at a car dealership?

 

[racerone]

It is a woodruff key.-----But it must not stick out too far.-----The key puts the flywheel in position for proper timing.-----The flywheel is driven by the locking tapers, when flywheel is torqued to 102.5 FT LBS.----Therefor tapers must fit properly.---Use lapping compound to check.=----Assemble CLEAN and DRY.

 

[Beakster]

Ok, I managed to find a Napa with a selection of Woodruff keys. I filed it down a bit and torqued the flywheel down, and it started right up so that was the problem.

Had her running on muffs for about 2 mins then the overheat alarm went off and she stalled. While she was running there was a steady stream of water from the tell tale. However I was seeing a load of water coming from other places which looked wrong. Seems water is also coming out from best the top mount bolts, see photo:

 

[jimmbo]

Did you take the Cowl off, and look for water coming out of the block?

 

[Beakster]

The engine was running with cowl off. Everything above the cowl base plate seems dry.

Heads were too hot to touch but back of thermostat housing was cool to touch.

I'll take off those covers you can see in my photo to better understand where the water is coming from

 

[Beakster]

I can't see any water coming out of the block. It pour out from here:



everything up top is dry. Could this be normal?


Heads get hot but thermostat cover is cool, is that normal?

Any way to test if thermostats are opening?

 

[Beakster]

I just disconnected that hose and ran the engine. I don't see any water coming out of it even though there is a good stream from the tell tale. Is that normal?

 

[racerone]

Fact----The water that comes out the tell tale does NOT circulate through the block.----You should have lots of water coming out of the hoses before the water visits the thermostats !!----Time to stop running this motor and find out where the blockage is !!!