C-28 D4-260 Engine Ground

[jkhiser]

Been chasing multiple electrical gremlins since I bought the boat.

Current Gremlin Symptoms: engine will start at the pier, but after a few hours underway, engine will not restart without parallel with house. Volvo gauge shows 14 volts, but just doesn't seem like any charge getting back into battery.

Finally got around to walking the positive and ground lines through every connection to the starter and alternator.

Did not find any obvious corrosion, but was surprised to find the connection from ground bus to engine frame (at starter) was seriously oversized for the connection post. I have been thinking I needed to change the ground connection lug to the proper size for the post, but am now wondering if the ground may have been moved from the factory location -- does not seem the factory would have made such an oversized lug.

Ground connections on starter prior to removal (positive connection to starter is removed for access)


Comparison of ground lug sizes sharing same post:


Attempt to show oversized lug on starter post:

 

[BB marine]

I don't think the factory (Fluid Motion) designed this install. Like many installs on our boats the install is done by a technician . When the technician was installing the engine, cables and accessories he had a choice to do it right or wrong. The technician chose wrong in the case of Negative battery connection. I will look at my connection today to see if this is a common practice. I don't think it is. You have two choices (1) do what the technician should have done and replace the end with the correct 5/16 or 3/8 lug size. (2) install the large diameter lug under the ground strap. Fluid Motion does a good job with installation of wire harnesses and cables. I believe their intent and commitment is to do it right. The build "was", "is" sometimes weak in the Quality control department. Speaking only from my experiences on my boat and a few owners that have commiserated with me. Quality Control is much cheaper then warranty repairs, in many ways.

The issue you are having with no start could be a bad battery. The 14 Volt reading is indicating output from the charging system (alternator) to the battery. I had the same issue with my house batteries. When charged with onboard charger or alternator the voltage reading would be 13.8 Volts. Then I turned the charging system off the voltage would stay right at 13.1 volts. I disconnected all terminals from the battery to eliminate the boat wiring. I load tested the fully charged battery, It failed "badly"!

 

[jkhiser]

I do know I have bad batteries, today is new battery day, set of Interstate Flooded, starting for engine and thruster, deep cycle for house.

But these batteries are only one year old, all replaced when I bought the boat, in that case with the original UB121100 AGMs.

Re: Fluid motion design - that cable is factory original, with the factory labels on both ends. So either the wrong lug got put on, or it got attached in the wrong place on the engine. The other end is correct at the ground bus. (But that has me thinking - why does it go to ground bus instead of back to battery negative? Will have to research, or see if I mis-traced the wire. Got all disconnected for battery change, so easy to trace with meter.)

At the survey, the engine was showing the same problem with starting. New battery solved it for a few months, before the problem returned.

As I said, electrical gremlins - hoping to find the problems before I had to throw a new set of batteries at the problem, but was not successful.

Now starting with new batteries, and going hand over hand through the entire system trying to find problems, and restore wiring to factory original when I find deviations.

And going with flooded, cheaper and can monitor water, etc., etc.

 

[Hydraulicjump]

I have the same engine and had start problems requiring paralleling with the house batteries. And this on fairly new batteries. Yes, the grounding system is suspect, but this problem was eventually solved by putting in a start battery with significantly higher CCA. Haven't had a gremlin problem since. Something to consider.

Jeff

 

[quinsky]

I considered replacing my starting battery with a flooded battery. I read the manual for the battery charger and discovered that it can be set up for AGM, Gel, or Flooded batteries but not a combination. It charges all three banks at the same setting so you need the same type batteries in each bank. I chose to replace it with an original Universal 110amp AGM. Not the best starting battery but cheaper that a new charging system. When I first start my engine I get a "Water in Fuel" alarm. I went through all the diagnostics and even replaced the sensor. Narrowed the problem down to voltage drop. I cleaned the starter connections which were not too bad but I didn't notice the size of the connections. If I start with the crossover on I don't get the alarm. Or I can let the engine warm up, shut it off, turn the engine battery switch off and on, and restart. It cranks right up when warm thus no major voltage drop and no alarm.

 

[BB marine]

I checked the ground terminal lug at engine ground. It has a 3/8 hole in the lug, the stud is 8mm very close to 5/16. A 5/16 lug or 3/8 is acceptable for this application. The lug in your photo looks like 1/2". not the right choice for the application but if it is faced up to a clean flat grounding surface and tight it should provide a usable ground. I would consider replacing the lug.




The engine negative terminal should be connected directly to the battery negative terminal. (A) second terminal can be connected at the engine negative terminal to the ground bus. (B) the ground bus can have jumper terminal connected to battery negative terminal. The ground bus connection in my boat uses (B)

This goes along with what Jeff stated. When purchasing cranking batteries compare apples to apples. Many marine batteries just have Marine cold Cranking Amps or Cranking amps. Other marine batteries have both Cold cranking amps and Marine cold cranking amps or Cranking amps. Marine Cold Cranking Amps is the same as Cranking Amps (tested at 32 degrees) . A Volvo D3 has a minimum of 800 CCA battery specification which is 1000 MCCA or 1000 CA. If the Battery only has a MCCA specification on it multiply the MCCA by .8 to get the CCA specification. The D4 may require a larger CCA battery then you are using.

 

[Cutwater28GG]

Brian how do you keep your engine mounts so clean and rust free!?

 

[jkhiser]

Brian -

Your ground configuration is completely different. On mine, the grounds come to a post up behind the starter. Looks like yours converge on the engine mount.

Also, the engine ground cable will not reach to the starting battery negative post, but is terminated on the ground bus forward of the starting batteries. I still need to rearrange the ground bus so the connection to the start negative is directly on the engine cable.

For the start battery I chose the Interstate 27M-XHD, 800 CCA and 1000 CA.

I added a steel washer to the ground stack so the oversized lug is well captured on both sides. May replace the lug, but the cable is already short.

 

[BB marine]

The Engine Ground terminating at the Ground Bus probably will not give issue but it really should go directly to the Battery ground terminal. Last year I moved 3 of my batteries to the starboard side to balance the boat so it did't list to the port. I have a terminal crimper but it was difficult to find heavy duty lugs at big box or auto part stores. I purchased all electrical connectors through Del City. I had plenty of cable to make the changes because the project required shortening the cable lengths. I did need 1 long 2/0 yellow cable for a Jumper from Cranking battery to House and thruster batteries. I called Gregs Marine wire supply, 724-589-0225 , gregsmarinewiresupply.com. He made up a custom cable based on my length dimension , 5/16 terminal lugs ,yellow, looks identical to Fluid motion cables for a reasonable price. I priced the cable, lugs and shrink tubing to make it myself, his price was cheaper.

Definition from ABYC requirements
f. Engine Negative Tenninal - The point on the engine at which the negative battery cable is connected.

All ABYC diagrams show engine Negative ground directly to Battery. Negative Bus terminal comes off the engine ground separately or the negative battery terminal separately.

It may not be your issue ( battery failure) but it does have a yellow Flag!

 

[Jeff58]

I had the exact same hot re-start problem after leaving the dock. Pulled the engine battery, tested at the gas station, replaced with Optima and corrected.