Yamaha Sages 25 and 50 dramas

[andrew j cox]

Question number one concerns a 02 Yam 50 hp 4 stroke, i need to rering this creature does the conrod break apart with two bolts as a car?

Question number two concerns a mid 90s Yam 25 hp, this motors is possibly buggered, guy was out fishing 8n fresh water river motor started to smoke and it stopped, takes to local mech he said impellors gone so replaced it and of he goes fishing again, this time it just stopped dead, not totally siezed but may as well be, he drops in my lap asking is there any hope?, i gave it a gentle pull and its real stiff, i could see the paint burnt off the head I asked if this so called mechanic checked the thermostat? Answer was I dont know, without further ado I popped the thermostat Ive never seen one more rooted, I;told him this was your problem your impellor was probly ok, i popped the plugs out the threads are permanently black from heat I have filled the bores with Inox, I did remove two head bolts, the others are stuck fast I could feel them wanting to break,
the chances of this motor ever running again are oretty remote? What say the experts.

 

[Sea Rider]

Are we talking about 2 or 4 strokes OB's ?

Extreme overheating will screw any reputed outboard not counting with an overheat sensor. If pistons can still move no matter if with restriction when pulling rope, tilt fully OB, remove spark plugs and spray an overdose of WD-40 inside both cylindres, let soak overnight, pull again, check if pistons moves without any restriction.

Need to retorque head and exhaust gaskets and base bolts to factory specs, if bolts are seized and won't budge a bit, will eventually break when trying to be removed from head. If managed for OB to work again change thermostat, could have been altered already. Check if head is already warped ?

What you have explained are typical symptoms of an extremely overheated OB. Been there several times due to algae blocking lower leg's water intakes and literally melting the impeller inside liner by rurring dry at speed, very bad music..

Happy Boating

 

[raczekp1]

with this 25 hp please remember about:
1.F-R antystart system.
2. if head bolts dont move i would pull the powerhead and heat all head bolts with acetylen torch to make loose bolts

 

[Sea Rider]

with this 25 hp please remember about:
1.F-R antystart system.
2. if head bolts dont move i would pull the powerhead and heat all head bolts with acetylen torch to make loose bolts

Would use a propane torch to heat up seized bolts rather than a acetylene torch..

Happy Boating

 

[andrew j cox]

After two two days of soaking the pots it still didnt want to free up to any degree, weve written this motor off as not worth any more effort
The 50 is a four stroke,
I dont know how you go for parts in the USA but here in oz you mention yamaha to a parts supplier they seem to lose interest,
I have an American import 25 Yam 4 stroke Ive been tinkering away on the idle jet in the carby had siezed into the housing, I had to drill it out, youd think such a simple part would be easy enough to track down, not so, ebay no good, I had an idea maybe some of the Yammy bikes might run a similar jet ive yet to investigate this.
With the amount of Chinese manufacturers using Yamaha powerheads now Im giving serious thought to importing in parts from China, same deal with Suzuki too, motors from 5 - 25 are very popular here we have practically millions of aluminium dinghys from 10 to 14 foot and jap outboards are well liked here, Yams and Suzukis very common. Kinda makes sense to find a better source of parts.

 

[99yam40]

Find the part # needed on Yamaha web site and then do a web search to find who you want to buy from