93 yamaha alarm sounding

Ray Neudecker

Lieutenant Commander
Joined
May 25, 2004
Messages
1,656
Re: 93 yamaha alarm sounding

You are wanting to deal with a very hazordas chemical with Muritic acid and water mix. If you had ever been around the fumes from it you would likely reconsider this shortcut effort to diagnosis and repair. Cooling problems can be caused by many things and troubleshooting can be a long process.
You have proved you have a heating problem , done some basic maintence that hasn't cured the problem. You could easily have a head problem, water passage problem or a base gasket that has been burnt up. Sometimes reading the plugs will help if water is leaking into a cylinder. Pulling the head would be the next logical step. This can be a major pain on engines which have been run in salt water.
Continuing to run the motor with a high potential for complete engine failure is not likely to be wise.
 

sunpacman

Petty Officer 3rd Class
Joined
Mar 19, 2005
Messages
94
Re: 93 yamaha alarm sounding

Yeah, I think the logical solution by process of elimination is to now remove the cylander head. This engine has been rebuilt but in uncertain of when,point being, the bolts look clean. What concerns should be considered when removing the head? Also, does the head cover need to be removed first? And lastley, does the heads need to be resurfacedonce removed?
 

sunpacman

Petty Officer 3rd Class
Joined
Mar 19, 2005
Messages
94
Re: 93 yamaha alarm sounding

UPDATE:
I was able to remove both c-heads today. Thero water holes are clogged bad...some water getting through but just not enough. see pics....

I br
oke (2) BOLTS off in the block taking them off..any help on how to get these out? I even broke off and easy out in one after drilling...damn-it!
:album
 

cnyman

Cadet
Joined
Jun 26, 2007
Messages
7
Re: 93 yamaha alarm sounding

Salt away treatment works well(available at West Marine and a lot of other catalog suppliers) If the tstats were bad looking, it is very possible one or the other was sticking intermittantly. The housing they are under contains the temp sensor. Before going bananas on attempting to clean the passages, replace the tstats and do a test run. Your situation is exactly the same as mine was with a 92 250hp. Replaced em and now good to go. If you run in salt, flush often and consider replacing those dudes every two years or so. Other poster suggested cooling sytem tune up. Good idea. The low pressure of the water system after the pump replacement indicates either a restriction or a water pump housing/tubing sealing issue. See if the tstats solve the alarm issue, keep looking into the low pressure issue. If the impeller was changed without changing the housing, this is why the pressure is lower on this engine. A seemingly small groove in the housing or base plate can dramatically reduce the pressure and flow. Good luck.
 

DjKoKo

Seaman Apprentice
Joined
Mar 1, 2006
Messages
47
Re: 93 yamaha alarm sounding

Wish I would have seen this post a while ago. I could have helped you along time ago! I had this happen to me last year and yep, the heads needed to be pulled and cleaned and it fixed her right up. (91 yam 115)
 

jjdluz

Seaman
Joined
Feb 4, 2008
Messages
67
Re: 93 yamaha alarm sounding

did u get your problem fix?and what is cause of the problem?
 
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