2001 Mariner 50hp four stroke problem

[Dobieman]

Hi All

I have a small problem with my outboard and am hoping someone can help....

It starts and runs perfect all day whether at 2000rpm / 5knts on the thames or higher revs cruising at 15 or 20 knts.

the problem is the warning buzzer sounds when it is left ticking over for more than a couple of minites, i can then turn it off, restart it and go on my way with no more problems until i leave it ticking over out of gear again.

There is plenty of oil in it so am thinking the only other thing it could be is an an overheat alarm?

Could the impellor be not pumping enough at tickover but as soon as the revs increase even by 500rpm it's doing enough to keep the engine cool?

The tell tale is pretty strong but not like the 50p 4/ Yamaha i owned previously which was a real jet of water at any revs.

Thanks...

[davej]

The best thing to do for piece of mind is to drop the leg off and if not replace the impellor, which I would do but at least look at it. The cost of the impellor will be about £15 to £20 and while I think you can get away with replacing bi annually, it should be looked at, if only to avoid the bolts siezing up in the alloy casting.

Good luck

[jyasaki]

I would guess it's either the impeller or you've got salt build-up in the water jacket.

Replacing the impeller would be a prudent first step (especially if you don't know when it was last done or if it's been more than a couple of years); it may well solve the problem.

If it doesn't you can either try running an acidic solution through (run the motor in a drum or similar with water and a healthy dose of vinegar), or take it to a shop and let them flush it out

Luck;

jky

[ribdraft]

had the same engine with the same problem, we tried all the usual stuff,and tried 3different dealers to get fixed, anyway cut a long story short, it was salt build up. you can put solvent threw and even blow it out , they work for us for awhile,but would start again weeks later, its was pipe from impeller that goes to head, we ended up replacing it , been fine since, 5yrs later

[Dobieman]

has anyone got a link with step by step instructions for changing the impellor? I'm fairly competent with the spanners but have never changed one. also does the vinegar and water really work? Never heard of it before. Thanks

[ribdraft]

would be the same with the spanners, but after the a year and a half of that buzzer going off and after spendin hundreds at dealers, i decided to go at it myself, wasn't that bad,just take your time, ended up taking head off engine and droppin leg to get knew part in,suprised my self, but it was pretty straight forward motor

[jyasaki]

Vinegar is an acid which helps dissolve salts. Cheaper than commercial formulations.

Shouldn't be too bad a job; remove the bolts holding the lower unit, disconnect anything that holds it together (shift lever and pitot tube, usually), take the LU to your work bench, and see how the impeller cover comes off (should be right where the driveshaft disappears.) Usually some kind of hose clamp like thing will be holding the cover on. Make note of how things come apart (there will probably be a bunch of washers and gaskets); the impeller will probably be mounted to the shaft with a woodruff key. If you can, replace the wear plate at the same time (the thing the impeller sits on.) Not rocket science, but it is a somewhat critical bit of mechanics, so take your time and make sure you do it right.

You should be able to get a kit for everything at your Merc/Mariner dealer. Might be worth picking up a shop manual as well. Might be able to find a step-by-step demo on the web if you search for "Impeller +[engine]"


jky

[spartacus]

Originally Posted by Dobieman

has anyone got a link with step by step instructions for changing the impellor? I'm fairly competent with the spanners but have never changed one.

This is a good link. Has step by step instructions and pictures.
http://rib.net/forum/showthread.php?t=5840

[jyasaki]

Just looked at the OP's bio and the post. Is it a Mariner or a Yammie?

There's a good tutorial on a US forum for Yamaha (in this case, an F115), don't know how it compares to Spartacuses, as I haven't looked at his.

jky

[Dobieman]

thanks guys, i'll attempt the impellor change and let you know how i get on....

[Swifty]

Have heard of an O ring between the leg and power head that swells up and restricts the water flow. Not an easy job but would try the impellor first!