Re: [OMC-Boats] Replacement Voltage Regulator

From: Lee Shuster <Lee.Shuster@...>
Date: Mon, 31 Aug 2009 09:58:27 -0600


Some very simple tools and basic checks that can be done in your driveway will be very helpful.

1) As I recall you re-did your instrument panel? So I'm not sure where you stand with your original ammeter, which would normally tell you the working state of your alternator and voltage regulator.

So know you simply need to:
a) start out with a fully charged battery, verified with a specific gravity reading and voltmeter.
b) Clean and recheck all cables and ground points.
c) Measure the primary side resistance of the coil with an ohmmeter and also measure the resistance of the ballast resistor, (both are relatively easy to replace).
d) Use an inductive clamp-on ammeter to measure charging/discharging rate, or insert your old ammeter in series with the positive battery cable lead going up to the helm (don't wire it in the battery's full circuit without using a shunt, as it doesn't have the capacity to handle the starter motor current draw and you will burn out the meter.)
e) As an alternative you could take your Prestolite Alternator and external voltage regulator into any decent motor-alternator shop and they could bench check it for you. (One of the main reasons GM-Delco and much of the industry went to an integrated, or built-in regulator in most alternators, is most people tend to overlook the regulator when troubleshooting alternator problems.)
f) Also, as previously mentioned, a simple voltmeter reading directly at the battery will show evidence of alternator charring. A properly operating alternator and voltage regulator will read about 13.9 to 14.1 after the engine has had time to recharge a fully charged battery battery after a normal turn-key (quick) start.

I'm not ruling out fuel problems at this point, but from what you have done (and not done) and what you describe as symptoms, I think you need to focus on electrical. The good thing is most of these checks can be done in your drive on the hose.


From: omc-boats-bounces@... [] On Behalf Of Scott Veazie
Sent: Monday, August 31, 2009 9:17 AM
To: omc-boats@...
Subject: Re: [OMC-Boats] Replacement Voltage Regulator


Sounds like some of the problems I had a few years ago, to a degree. I would certainly replace the coil, a weak coil will work well cold but with engine heat it will degrade performance as heat builds up. Also, do you have a clear fuel filter near the carb? I'm not sure they're compliant with USCG regs...but if you have a nice glass clear one that can be disassembled you can see what's going on and clean it out. When my Seasport that I had would go along at a good clip and then run out of gas, I found it to be fuel starvation due to the fact that there was a clog. What I would do it get her on plane, and then run back and look at the filter to see how much fuel was in it. It's advisable to do this with two people, but I managed. Also, one other thing you didn't mention replacing is the fuel pump. My '65 Chev truck would do the same thing when the pump was checking out. Either replace it with another mechanical or go electric.


Date: Mon, 31 Aug 2009 07:35:59 -0700
From: bldfw@...
To: omc-boats@...
Subject: Re: [OMC-Boats] Replacement Voltage Regulator

OK....Then let me share my latest symptoms......

Previously I had rebuilt the carb and enjoyed several successful runs back and forth across the lake but as the hour ran on, performance slowly started to denigrate due to poor gas. I followed that up by cleaning the tank and replacing plug wires.

Since then I've experienced fuel starvation symptons wherein it would get up on plane but then within seconds would die and then be restartable right away and repeat again. It would run good at lower RPM's but then die as soon as you got her up on plane. As before, as the hour ran on, performance would denigrate and would get prrogressively harder to start from lack of battery power. With the lack of apparent charging and being told by the alternator repair company that it was bad, I replaced the alternator with a completely new (not rebuilt) one.

Last weekend, same thing. It would bog down as the throttle opened. I was able to get up on plane only briefly once. I may have contributed to that by changing the idle set screws. While we were out I noticed the top of the carb was wet so we shut down and I adjusted the float thinking it was allowing too much fuel. Mistake. On the way back to the marina I could only get 1500 RPMs max and it would start to bog down. By the time I got back to the loading ramp it was hard to keep her running.

When I got home I removed the carb again. I found a little bit of residual mud in the bottom of the fuel bowl which is believed to have come from the dirty gas on the one run after the rebuild. I did some prefunctory cleaning. Gas is running clean and carb is clean. I readjusted the idle screws by closing them and then backing them out 2.5 turns this time.

Yesterday, I took her out and still encountered problems. I was able to get up on plane with RPMs up to 3400 before encountering problems. Without touching the throttle she started to slow down. I purposes left the throttle alone. The RPMs slowly started to come down to the point of barely running but it didn't behave as though it were gas related. It just felt like it was running weaker and weaker. When it died, I had trouble starting. I'd turn the key and nothing! Nada....then a click, then the rattling of the solinoid as you get on a low battery. Turning the key on and off a few times I was able to get it crank over weakly and she'd start right up again. That repeated until insufficient power to restart. I had a rescue buddy hanging with me for that purpose so we tied the boat up behind his house boat and went off to enjoy the afternoon (sans using my boat).

After a couple of hours we tried the key again. It had sufficient power to crank but I told him to just tow me back to the marina as I'd need what little power might be left to get to the boat ramp. Sure enough, it started but by the time I idled over to the boat ramp, it would barely run and eventually died with no power to restart.

Here's what I've done thus far:
-- New battery
-- New plugs, points, condenser.
-- New plug wires (checked and rechecked multple times)
-- New alternator
-- Dismantled, soaked and cleaned carb
-- Removed, dumped and cleaned fuel tank
-- New fuel filter (still showing clean with not particulates)
-- Timing is set a 5 BTDC per the manual.

Thinks I have not done yet:
-- Voltage Regulator
-- Coil
-- Sell boat.

I'm open to any and all suggestions!

Dallas, TX
1970 Evinrude Explorer - 155 Buick V6 - OMC Sterndrive

--- On Mon, 8/31/09, Lee Shuster <Lee.Shuster@...> wrote:

From: Lee Shuster <Lee.Shuster@...>
Subject: Re: [OMC-Boats] Replacement Voltage Regulator
To: "Evinrude & Johnson Boats of the 1960's and 70's" <>
Date: Monday, August 31, 2009, 8:40 AM

Croos-reference BRP/OMC part No 383440 (Always shown as part of Cooling Group, due to mounting location). Sierra, and BRP/OMC should all stock these. They are still fairly common at this point.


PS -- These rarely fail. The single most common cause of failure is when owners install and improperly load-switch a dual battery system.

From: omc-boats-bounces@...<http:///mc/compose?to=omc-boats-bounces@...> [omc-boats-bounces@...<http:///mc/compose?to=omc-boats-bounces@...>] On Behalf Of BLDFW [bldfw@...<http:///mc/compose?to=bldfw@...>]
Sent: Sunday, August 30, 2009 8:33 PM
To: omc-boats@...<http:///mc/compose?>
Subject: [OMC-Boats] Replacement Voltage Regulator

Just checking on a good source for a replacement voltage regulator.

Prestolite VSC-2602E 12y

I'm browsing now so now would be a good time to get a response (Lee, I see you still out there posting away!). ;-)

Dallas, TX
1970 Evinrude Explorer - 155 Buick V6 - OMC Sterndrive

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Received on Monday, 31 August 2009

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