Yamaha 4hp Outboard, Help Please!

[Alistairr]

I bought a secondhand 4 stroke o/b last year, and cause of recent events i only got too run it up for the first time, last weekend.
Once i put the oil and fuel in it, it fired up on the second pull and ran great!
I only ran it for a few seconds, I was just testing it, with it hooked on the back of the Sealine, it wasn't till later when i was enjoying a nice Malt, that i realised i didn't see any 'Tell Tale' water coming out of the engine!
So i fired it up again, and i was right, a couple of drips but nothing! Not wanting too do any damage, i turned it off straight away.

There is no mention in the manual as too where the impellor is, or if this is normal, what i have found out this week, the earlier models were fitted with a thermostat, and other than a couple drips, it won't flow till its properly heated.
Could this be the case? Does anyone with a Yamaha 4hp agree with this?

If i run it for a few minutes, do i not risk damaging it if its not the case??
BTW, not sure what the year is, maybe late 90's or a 2000 model.

Any help will be much appreciated.

Cheers

Alistair.

 

[Vagabond]

Check if the little rubber tube is blocked that shows if it's pumping water.

It's generally only a little tell tail and doesn't have much pressure as the water goes out with the exhaust.

I've had 2 where this has been the case.

 

[Alistairr]

[ QUOTE ]

Check if the little rubber tube is blocked that shows if it's pumping water.

[/ QUOTE ]

Ok i'll do that, now where will i find this 'little rubber tube'??

Thanks,

Al.

 

[Vagabond]

Take a look at the back of the engine for a tell tail hole where the water should be coming from. It's either right at the back or on the side somewhere.
Then trace it back from the inside.
In my case it only needed a squeeze to get the crud out of it.

 

[cliff]

There was no little rubber tube on either of the 4hp 4stroke yamahas I used to have - one had a stat one did not - one would piss water out of the widdle hole below the block from startup the other only after it had warmed up. Look under the block and you will see a little hole about 2mm dia - that is the widdle hole. At late 90's IIRC you have one with a stat but I stand to be corrected.

 

[Dave_Snelson]

Alistair - I fixed one of these for a friend. But first things first, with the engine running (you won't damage it for a minute or two) blow the tell-tale with an air line to check if its blocked. If no luck, switch off.

The impelor is in the lower leg. You will see a blanking rubber grommet on the side of the lower leg, pop that out to reveal the likage assembly for the gear, undo this. Undo the bolts that hold the lower leg and gear case to the leg and lower it down. The pump is on top of the gear case, undo the bolts and slide it off. Dismantle the pump and you may find the impellor in bits (that's what I found). Relace same, you can buy a water pump kit and reasssemble in reverse order.

Hope this helps
Dave

 

[Alistairr]

Yip, i know where the tell tale hole is, i checked it was clear ok. I will try following it back to see if i can find a bit of clear tubing.

Al.

 

[Questor]

Alistair

I have this happen on my Yamaha 8. On the Yam it is a metal pipe. The water flow slows down to virtually nothing, and I find by sticking a pin up the pipe, it starts to squirt fine again. The water when it comes out is only slightly warm, so overheating is not an issue.

Strange 'cos I never can feel any crud etc etc up there.

I always run the engine in fresh water after use for a couple of minutes or so, but maybe this isn't long enough to remove all salt deposits. I was thinking of running it for an extended period in some warmish water to see if that sorts it.