Questions regarding the charging/cooling system on 1989 5.7 Mercruiser

[rhillman75]

I have just a couple of questions to ask the pros, because I?m not sure what avenue to take. I have 3 batteries on board my 1989 Regal Ambassador 233XL separated by a Perko switch. I used my onboard test switch and saw them about 40%. I disconnected all 3 batteries, took them to my bench and charged them 3 amps for 24 hours and then their capacities were back to 95%. I reinstalled all 3 batteries, started the engine for the first time today, and when I increased the idle to 1,500 rpm the voltage gauge on the dash went from 14 volts to maxing out at 16 volts. At that point I used 2 different voltmeters and my Snap On battery tester and confirmed I had readings in the 16.4 volt range while the engine was running. What was weird was when I originally started the engine, the batteries all read 14.4 volts. Why such a difference and is their something I am missing. My other question is the cooling system. I had the engine running on the muffs and my temperature gauge on the dash started to rise past the halfway mark. When I increased the idle to 1,500 rpm, the temperature did go down, but started to rise once again when I returned it back to idle. The impeller was replaced 2 years ago and the thermostat last year (160 degree thermostat). I pulled the thermostat housing and flushed the engine with the plugs removed from the block and manifolds. There was ?some? pieces that came out of the manifolds but they were minute in size (probably less than a pen tip size). I let the engine run about 20 minutes on the muffs at idle but never let the temperature get passed the ? mark. I did come across the water pick hose having some cut marks in it from age since I did see ?some? water coming from it while the engine was running. On our last trip out last summer I let my son drive and I saw the temperature going up while at cruising speed and trimmed up, but the temperature dropped after we slowed down. I am hearing those that they say the manifolds are gone, but I would have assumed that I would have had more than just ?some? tiny pieces coming from the drain plugs. Thoughts?

One last thing, I went to Mercury Marine Parts Catalog, put my serial number, but could not find an impeller kit for the life of me.

Engine: 0C525595
Drive: 0C632122

 

[NHGuy]

Try to ascertain that the battery switch works right. But also I'd run the engine with just one battery to see if the voltage stays way up, If it does you want to rebuild or replace the alternator. It has a built in voltage regulator that's possibly failed. It's electrically like a car alternator but it's physically shielded so it's internal sparks can't ignite fuel vapors that are often present in a boat bilge.

Your drive serial # is for an Alpha 1. I put it in the catalog and it came right up. Which hose are you calling a water pickup? The one from the transom to the engine? Whichever it is, water escaping isn't cooling the engine so fix that first. Then let us know how it does.
Most alphas have an impeller in the lower drive.
There must be water to the impeller when the engine runs. If you have ever run it without water to the drive the impeller will be croaked, so if that's the case replace it again.

 

[alldodge]

I have just a couple of questions to ask the pros, because I’m not sure what avenue to take. I have 3 batteries on board my 1989 Regal Ambassador 233XL separated by a Perko switch. I used my onboard test switch and saw them about 40%. I disconnected all 3 batteries, took them to my bench and charged them 3 amps for 24 hours and then their capacities were back to 95%. I reinstalled all 3 batteries, started the engine for the first time today, and when I increased the idle to 1,500 rpm the voltage gauge on the dash went from 14 volts to maxing out at 16 volts. At that point I used 2 different voltmeters and my Snap On battery tester and confirmed I had readings in the 16.4 volt range while the engine was running. What was weird was when I originally started the engine, the batteries all read 14.4 volts. Why such a difference and is their something I am missing.

If your getting 16.4 volts at the alternator with a known good meter, I would remove the alternator and have it tested. My guess is the regulator has gone out.

My other question is the cooling system. I had the engine running on the muffs and my temperature gauge on the dash started to rise past the halfway mark. When I increased the idle to 1,500 rpm, the temperature did go down, but started to rise once again when I returned it back to idle. The impeller was replaced 2 years ago and the thermostat last year (160 degree thermostat). I pulled the thermostat housing and flushed the engine with the plugs removed from the block and manifolds. There was “some” pieces that came out of the manifolds but they were minute in size (probably less than a pen tip size). I let the engine run about 20 minutes on the muffs at idle but never let the temperature get passed the ? mark. I did come across the water pick hose having some cut marks in it from age since I did see “some” water coming from it while the engine was running. On our last trip out last summer I let my son drive and I saw the temperature going up while at cruising speed and trimmed up, but the temperature dropped after we slowed down. I am hearing those that they say the manifolds are gone, but I would have assumed that I would have had more than just “some” tiny pieces coming from the drain plugs. Thoughts?

Suggest checking your power steering cooler for pieces, If that's clear next thing I would check would be the exhaust manifolds and elbows

One last thing, I went to Mercury Marine Parts Catalog, put my serial number, but could not find an impeller kit for the life of me.

Engine: 0C525595
Drive: 0C632122

Your engine and drive numbers check out, just make sure your using a zero as the first digit and not an O.