bad timing killed my impeller?

[ryan04]

Hey guys,1972 125hp johnson. The timing started to act funny at the beginning of this season when I changed my oil and did a few other things to prep for boating. I had replaced the fuel lines and pump because they had never been done. The motor still skipped but the engine always ran at a good temp. I put a carb kit on the carbs and very slightly I mean very slightly adjusted one of the timing screws. Right after you could play the piano to this thing it was so consitantly beautiful, but then it started to get hot. Water was still coming out of all the usual spots, but after a minute or so the engine became quite hot, but there was water coming out of the tell tale's. I shut it down for the evening, then fired it the next day. Water was pumping good on the hose and engine off but as soon as I start the engine the water stops flowing out of the holes.
QUESTION 1- Could bad timing have killed my impeller?
QUESTION 2- Should I replace just the impeller or the whole water pump kit?
QUESTION 3- Is there a way to test my thermostat as well, and should I replace that as well?

That's all my rediulous questions for now, any comments will help. I have all the literature I need to do the job and am quite capable of doing so.

 

[F_R]

Re: bad timing killed my impeller?

I don't see how the timing could kill the impeller
If you don't have the plastic water pump, it would be wise to change out the whole kit.
Put the thermostat (vernatherm) in hot water. Should expand at spec temp, but I don't know what that is offhand 140 deg???

Put that timing back where it belongs. Preignition happens easy and will eat pistons.

 

[OBJ]

Re: bad timing killed my impeller?

No....don't think timing would kill the impeller.

Depends on the cup and plate. If they are ringed out pretty good, replace them. Put the whole kit in anyways....can't hurt.

If your not sure of the t-stats (which I would believe is the problem) replace them. If your not sure of the last time the were replaced.....replace them.

If over heat still occurs, there is other problems like deflectors in the block. But for now, I would go with the t-stats, impeller or both.

 

[Silvertip]

Re: bad timing killed my impeller?

And just to clarify, just because the tell tale is showing a good stream does not mean the engine is being properly cooled. The tell tales merely tells you the water pump is working. A stuck thermostat(s), malfunctioning popet valve, bad deflectors, a water jacket full of sand are just a few things that can cause an overheat condition even if the water pump is working fine.

 

[Xcusme]

Re: bad timing killed my impeller?

......but then it started to get hot. Water was still coming out of all the usual spots, but after a minute or so the engine became quite hot, but there was water coming out of the tell tale's. I shut it down for the evening, then fired it the next day. Water was pumping good on the hose and engine off but as soon as I start the engine the water stops flowing out of the holes.

Just a thought....when he started up the next day, water was flowing 'on the hose' motor off...start motor...water stops.....how about a blown head gasket pressurizing the water jacket blocking water flow?? I guess a compression check would/could reveal that and/or plug inspection for steam cleaning...
What are the chances, besides the usual suspects already mentioned?

 

[F_R]

Re: bad timing killed my impeller?

I noticed that comment too. Normally, I would expect the water pump to block the flow when it isn't running because it can't get past the stationary impeller. I'm guessing a badly worn out pump, especially if it has an aluminum housing. Or maybe a spun impeller hub. Anyway, the pump certainly is the first place to look.

Head gaskets and exhaust gaskets are a possibility. Especially if that thing has run hot.

 

[Texasmark]

Re: bad timing killed my impeller?

Bought the same engine new in '72. Family had tons of fun with it and never replaced anything except maybe plugs. Really sounded sweet when running at WOT.

With that vintage engine, you need to stop what you are doing, remove your lower unit and inspect your water pump. Replace what you need to and many instructions can be found on here because the issue has been hit many times.

I don't know it that engine had a thermostat or not. Need to ask a knowledgeable person on here. If it did, I'd pull it and check it for proper operating.

Mark