perkins 4 108 solenoid and starter

[jamesbuehner]

Disapensia will be missing her splash date, which was supposed to be the 27th of June.

The Perkins' starter spins but the solenoid fails to slide the appropriate gear to turn the engine over. Gentle knocks with my wooden handled carpenter's hammer have failed to coax any engagement. A further suggestion at the boat shop where she was painted was to wallop the starter with high amps from a battery charger, which I have yet to try, not to mention, figure out how to do.

I am asking for help and suggestions. The engine manual recommends removal and inspection of the starter, which is akin to threading a needle IN a haystack. Any thoughts would be appreciated.

Jimmy Buehner

[David van den Burgh]

We were having intermittent starting issues that prompted me to pull the starter and replace the solenoid. I'm not sure if your 4.108 configuration is the same as ours, but getting the starter out and back in place wasn't all that difficult. Better to go through the trouble dockside than to be without an engine when you really need it.

Sorry I don't have any recommendations about giving it a charge of electricity.

[Oswego John]

Hi Jimmy,

If I'm not missing something, I believe that the solenoid provides electric power to the starter. Since the starter spins, I would think that the solenoid is okay. Have someone check the DC voltage at the starter's electrical terminal for full voltage while the starter is running. Also check for fraying, oxidation or other corrosion problems at the wire terminals which could be the cause of high resistance.

If your starter system incorporates a Bendix type throw-out drive, I have most always found that the travelling pinion gear on the starter shaft doesn't engage the flywheel gear because it is dry. Inertia at the moment of starting should cause the pinion gear to spin easily on a heavy threaded part of the shaft and cause the gear to travel toward the flywheel.

It might pay to check the Bendix mechanism and lubricate it if necessary. Whether you have a Bendix drive or another type, my guess is that the starter's gear isn't travelling toward the flywheel for some reason or another. Another thought is maybe the starter motor doesn't start with high enough torque to create enough kick inertia to move the starter gear toward the flywheel. I would check for a dry shaft and dry threads first.

Without removing the entire starter motor, first look to see if there is a removable cone cap that shields the starter and flywheel gears from contamination. If so, removing the cap should allow you to inspect and lube the mechanism.

Let us know how you made out.

Good luck,
O J

[jamesbuehner]

John, thanks for your suggestions:

After careful cleaning of electrical connections/terminals etc that produced only the spinning starter , I jumped ship Saturday discouraged when I discovered the starter spun as I switched the isolator to the start battery position. No need to depress the start button.

Whoa! I'll tackle this tomorrow. Returning this afternoon, nada happens. No spinning anything. No response at the starter button, period. Isolator switch decides it's not a start button. In this kind of situation, since it's late in the day, I took a nap in the vee berth. And, upon waking, more cleaning and organizing. I shall try your lubricating suggestions on the morrow. I'm not sure what you mean by Bendex, a type description? My assumption is thie solenoid is a Lucas unit.

Jimmy

Jimmy

[Oswego John]

Bendix is a company that manufactures starter motor components.

Google "Bendix starter drive".

Take a set of jumper cables and using the red conductor, place one clamp on the starter motor nut and flash the other end on the battery's positive anode. See if this cranks the engine over.

Good luck,
O J

[jamesbuehner]

John

There's 12.8 volts at that nut (big nut at the end of the solenoid). Is this the nut you mean? I find this job daunting: can't get to it, so much piping in the way, though the forward end of solenoid is clearly visible and accessible. Can't really get to nuts of starter. Do I have to remove piping from exchanger to manifold in order to gain access?

Jimmy

[David van den Burgh]

John,
Do I have to remove piping from exchanger to manifold in order to gain access?

Jimmy

I'm not John, but, if I'm remembering correctly, I don't think I had to remove any of the cooling lines. There are slight variations with the 4.108, however, and yours might pose some challenges. Here's what ours looks like:



Edited to add pics of Ariel's solenoid and starter:

[Oswego John]

Hi Jimmy,

I don't know what type solenoid you have. Is it remote or attached on top of the starter?

Maybe the best thing to do is for you or someone you know who knows how to, send in a picture of the starter and of the solenoid.

Did you try the jumper cable from the battery to the starter? What happened?

Good luck,
O J

[tartansailor]

Hi Jimmy,

If I'm not missing something, I believe that the solenoid provides electric power to the starter. Since the starter spins, I would think that the solenoid is okay. Have someone check the DC voltage at the starter's electrical terminal for full voltage while the starter is running. Also check for fraying, oxidation or other corrosion problems at the wire terminals which could be the cause of high resistance.

If your starter system incorporates a Bendix type throw-out drive, I have most always found that the travelling pinion gear on the starter shaft doesn't engage the flywheel gear because it is dry. Inertia at the moment of starting should cause the pinion gear to spin easily on a heavy threaded part of the shaft and cause the gear to travel toward the flywheel.

It might pay to check the Bendix mechanism and lubricate it if necessary. Whether you have a Bendix drive or another type, my guess is that the starter's gear isn't travelling toward the flywheel for some reason or another. Another thought is maybe the starter motor doesn't start with high enough torque to create enough kick inertia to move the starter gear toward the flywheel. I would check for a dry shaft and dry threads first.

Without removing the entire starter motor, first look to see if there is a removable cone cap that shields the starter and flywheel gears from contamination. If so, removing the cap should allow you to inspect and lube the mechanism.

Let us know how you made out.

Good luck,
O J

X2

Dick

[Oswego John]

Hi Jimmy,

A large percent of starting problems is because of a poor ground for the engine. Make sure that the engine has a clean, secure ground both electically and mechanically.

Dave sent in some pictures of his starter and solenoid. I hope that your starting system is like, or close to, Dave's. Let me explain a little more what happens when you try to start your engine.

Your starter's electrical system is comprised of two distinct types of wiring. There is the primary circuit which uses a small size wire and also there is the secondary circuit which uses much larger, heavy battery type cable.

The starter is an electrical motor than draws a heavy amount of amps. The solenoid, or starter relay is a device whereby a small amount of amps of the primary circuit will control the delivery of a huge amount of amps via the secondary wiring to energize and drive the starter motor.

The solenoid or starter relay, the round metallic tube atop of the starter is an electro-magnet. The primary wiring passes through the key switch, starter push button and other components in order to supply a low amount of power to activate the electo-magnet.

When the magnet is activated, it closes two heavy copper contacts inside of the solenoid, (you can hear the click, click) which allow the heavy inrush of amps to the starter windings which, in turn, crank the engine.

Yesterday, I mentioned that you might try placing a jumper cable from the battery directly to the starter's feed. That method will work effectively on a starter with a remote solenoid. However, if your starter assembly is like or similar to Dave's, by placing the hot jumper cable on the large nut on the solenoid, nothing will (should) happen.

Even though you found that the secondary wiring delivered 12.8 volts at the solenoid nut, the starter will only start when the primary control circuit is activated which passes electricity through the electro-magnets windings and closes the heavy, secondary internal contacts.

There are several ways to energize the electro-magnet and test the primary wiring. Go through the normal drill, turn the key, push on the starter button, or do whatever is necessary on your boat for normal starting.

Another easy test is to place a screwdriver blade or pliers handles across the large nut and shunt it to the small 8x32 threaded post where the primary wiring is attached to the solenoid. There is constant 12 volts present at the large nut. A jumper from the nut to the control terminal for the electro-magnet should activate it and create the click which starts the engine. If you look at the picture of Dave's solenoid, you can see the large nut and also the small, threaded terminal post for the primary attachment.

By the way, I have a lot of boatowner friends who now carry a small jumper with alligator clips in their tool box. It is handy when their is some unknown malfunction in their starter's primary circuit. The jumper will help to get your engine started and get you home where you can spend some time trouble shooting at the safety of the dock or mooring.

Good luck,
O J

[sharkbait]

Many starter solenoids can be disassembled and a temporary fix applied to get home. Inside the starter solenoid is a large copper/brass disc and usually two large studs. When the solenoid is activated the large disc is pulled into contact with the studs causing current to flow from the power input stud across the large disc and into the starter motor via the second stud.

If your solenoid can be opened a quick repair is to turn the large disc over so the unused side will contact the studs. You can usually rotate the studs about 180 degrees so the disc contacts a unused portion of the stud. If any of these components cannot be repositioned you can still clean the contact area and reassemble.

[Matt Cawthorne]

Depending on the individual boat, getting the starter out can be very difficult. On my 36 I spent all day trying to get the thing out. The nuts are blind because the engine is so close to the hull. The other end of the bolts requires 5 foot long arms with three elbows each. Actually, I used 3 socket extensions and two U-joints to tighten the bolt while the person on the other end caught the nut end on with an open end wrench. I have heard others say that the job was easy. All that aside, the solonoid, is by comparison easy to replace. Two bolts, both of which you can put your hands on (+ the electrical contacts). If your perkins is like most, the rear seal leaks and everything in the bell housing is well lubricated. It shouds as if the solonoid is potentially the problem. It is relatively inexpensive ($100 or so) compared to a new starter motor or a rebuild. If I were in your shoes, I would replace the solonoid and see what happens. Disconnect the batteries first.

[Oswego John]

Disapensia will be missing her splash date, which was supposed to be the 27th of June.

The Perkins' starter spins but the solenoid fails to slide the appropriate gear to turn the engine over. Gentle knocks with my wooden handled carpenter's hammer have failed to coax any engagement. A further suggestion at the boat shop where she was painted was to wallop the starter with high amps from a battery charger, which I have yet to try, not to mention, figure out how to do.

I am asking for help and suggestions. The engine manual recommends removal and inspection of the starter, which is akin to threading a needle IN a haystack. Any thoughts would be appreciated.

Jimmy Buehner

Matt, I agree with the problem with the starter's removal. Replacing the solenoid is a much easier job than removing the starter on some boats.

The reason that I thought that the Bendix drive unit might be dry was because Jimmy mentioned that the starter was getting juice and spinning, which means that the solenoid was transmitting power to the starter.

Another possibility is that the solenoid secondary was making poor contact and was restricting a full flow of power to enable the starter to snap into high revs when energized. This desired snap start is what overcomes inertia which causes the Bendix drive to unscrew itself and cause the pinion gear to mesh with the ring gear on the flywheel.

Under such a condition, a new solenoid might prove to be fruitful. Unfortunately, if Jimmy's starter is the same as that in the picture that Dave sent in, the starter will have to be removed to lube the dry Bendix drive.

Ah, the joys of boat ownership.
O J

[Matt Cawthorne]

If I am not mistaken on this unit, the solonoid actually pushes a lever that drives the pinion into engagement. If that is true, then the solonoid could be the reason for lack of engagement. Also, removing the solonoid provides a degree of access to lube the pinion.

If it is like my perkins 4.108, you may need a blowout preventer to keep the oil from gushing out. I have tried submersing the engine in drilling mud to stop the oil flow, but that leaves the aft end of the boat sitting low in the water. When I had the bell housing off I made the critical mistake of not drilling a relief well.

[Stan W.]

Starter solenoids are more than just relays. They also physically move the pinion gear into engagement with the starter ring. If the starter spins but doesn't engage, it's the solenoid.