Community Forums

YC1 · 01-06-2018, 07:59 AM

Cold air is more dense. If the carb is a bit sickly the mixture could be a bit off.

I think the carbs are not too expensive. Your maintenance is a bit overwhelming.

I don't know what plugs you are using but NGK center fire type plugs have given me better performance in some situations.

Dav L · 01-06-2018, 10:33 AM

Quick read and it seems like there are two sets of symptoms.

When you are cranking the generator to start...does it turn over normal speed? If so, electrical should be fine. It's not the battery, not the relay, not the starter, not the wires.

Sluggish to start I agree with most of the posts to rebuild and clean the carburetor. Sounds like it's just not getting rich enough mixture. The "hunting" could be due to slightly lean mixture. That could be as simple as a 1/4 turn open on the high speed mixture screw. I seem to remember the carb is easy to get to and remove. A quick shot of ether will confirm if it's fuel related or not. (let's not discuss ether issues - there's another thread going on about that already).

I don't think the carb needs to be replaced, since it seems to run for the most part...just needs some loving care.

Waiter21 · 01-06-2018, 10:57 AM

My old 2001 Mirada had a 4000 Microquite that didn't like cold weather.

I readjusted the choke, and this cured the starting problems. Hold the STOP button in for about 15 seconds before attempting to start. This forces the fuel pump to run to make sure it has fuel in the carb bowl.

Onan Generator Choke Adjustment – 2001 Coachmen Mirada 300QB

I haven't had any cold start problems with my older 1999 Southwind (Marquis 5500). I did a complete service on it right after I bout the MH last spring.

Onan Marquis 5500 Generator Service – 1999 Southwind 35S

..

Dav L · 01-06-2018, 11:39 AM

"Hold the STOP button in for about 15 seconds before attempting to start. This forces the fuel pump to run to make sure it has fuel in the carb bowl."

Interesting...did not know that.

cimplexsound · 01-06-2018, 12:14 PM

Quote:

Originally Posted by Waiter21

My old 2001 Mirada had a 4000 Microquite that didn't like cold weather.

I readjusted the choke, and this cured the starting problems. Hold the STOP button in for about 15 seconds before attempting to start. This forces the fuel pump to run to make sure it has fuel in the carb bowl.

Onan Generator Choke Adjustment – 2001 Coachmen Mirada 300QB

I haven't had any cold start problems with my older 1999 Southwind (Marquis 5500). I did a complete service on it right after I bout the MH last spring.

Onan Marquis 5500 Generator Service – 1999 Southwind 35S

..

Very cleaver. Thanks.

cimplexsound · 01-06-2018, 12:16 PM

Quote:

Originally Posted by YC1

Cold air is more dense. If the carb is a bit sickly the mixture could be a bit off.

I think the carbs are not too expensive. Your maintenance is a bit overwhelming.

I don't know what plugs you are using but NGK center fire type plugs have given me better performance in some situations.

The spark plugs I am using are the ones that recommend in manual.

cimplexsound · 01-06-2018, 12:38 PM

Ok here's what I now know so far. After starting the generator this morning I determined one thing. It's like the starter isn't getting enough power. The generator starts right away with no hesitation once I do get the starter to work. The starter motor is mechanically sound and in good working condition. The starter relay switch or what is often known as the starter solenoid relay switch, is suppose to take low amperage battery power and boost it enough to deliver sufficient power to the starter so it can set the engine in motion. With everything else testing OK including the starter motor, the relay seems to be the issue. I do know when the solenoid relay switch is going out (especially in cars) it can draw an overwhelming amount of power from the battery because it no longer has the ability to amp the power enough to turn the motor so the switch over works as it burns out. The relay switch is about $25 to $30 online and only takes about 10 minutes to replace. So I'm going to order the switch and we shall go from there.

YC1 · 01-06-2018, 04:19 PM

Ok here's what I now know so far. After starting the generator this morning I determined one thing. It's like the starter isn't getting enough power. The generator starts right away with no hesitation once I do get the starter to work. The starter motor is mechanically sound and in good working condition. The starter relay switch or what is often known as the starter solenoid relay switch, is suppose to take low amperage battery power and boost it enough to deliver sufficient power to the starter so it can set the engine in motion.The relay/solenoid is a simple electric on off switch controlled by a low power control line. The starter switch in this case.
The solenoid is supposed to become a dead short. IF you carefully use a car jumper cable across the two large wires or other suitable size jumpe you can bypass the solenoid for a test.

With everything else testing OK including the starter motor, the relay seems to be the issue. I do know when the solenoid relay switch is going out (especially in cars) it can draw an overwhelming amount of power from the battery because it no longer has the ability to amp the power enough to turn the motor so the switch over works as it burns out. The solenoid contacts become burned and arched and will not allow enough current to flow. Take it apart when you get the new one and you will see the problem.The relay switch is about $25 to $30 online and only takes about 10 minutes to replace. So I'm going to order the switch and we shall go from there.

So to be clear. The solenoid does NOT amp anything. It is just a simple enclosed knife switch.

cimplexsound · 01-06-2018, 10:50 PM

Quote:

Originally Posted by YC1

Ok here's what I now know so far. After starting the generator this morning I determined one thing. It's like the starter isn't getting enough power. The generator starts right away with no hesitation once I do get the starter to work. The starter motor is mechanically sound and in good working condition. The starter relay switch or what is often known as the starter solenoid relay switch, is suppose to take low amperage battery power and boost it enough to deliver sufficient power to the starter so it can set the engine in motion.The relay/solenoid is a simple electric on off switch controlled by a low power control line. The starter switch in this case.
The solenoid is supposed to become a dead short. IF you carefully use a car jumper cable across the two large wires or other suitable size jumpe you can bypass the solenoid for a test.

With everything else testing OK including the starter motor, the relay seems to be the issue. I do know when the solenoid relay switch is going out (especially in cars) it can draw an overwhelming amount of power from the battery because it no longer has the ability to amp the power enough to turn the motor so the switch over works as it burns out. The solenoid contacts become burned and arched and will not allow enough current to flow. Take it apart when you get the new one and you will see the problem.The relay switch is about $25 to $30 online and only takes about 10 minutes to replace. So I'm going to order the switch and we shall go from there.

So to be clear. The solenoid does NOT amp anything. It is just a simple enclosed knife switch.

Yes I am fully aware the starter solenoid is inside the case. I discovered the location of the switch when I first bought this Motorhome. It was then I took the main board off the generator case and cleaned it at the time I first started working on the generator and got it in working condition. I have physically inspected the solenoid already. It's not burned. This generator only has a little over 500 hours on it. The solenoid switch does look old and corroded. So the inside of the switch is probably all gummed up with dirt and grim, since these generators are exposed to road debris as you drive. Nonetheless I agree with you on one thing. The relay has to go. It looks like it has defiantly seen better days. No doubt I also agree as the solenoid switch ages, it burns up inside. YC 1 I don't think there's really a way to take the switch apart. It looks like it is a factory sealed piece. Basically a throw away when you replace. Just like most automotive parts today go figure.

Dav L · 01-06-2018, 11:23 PM

"A stater relay switch is an on/off capacitor type switch that takes the load off the battery. Without it you would burn up the battery. I've had the miss fortune of seeing people do just that to. Yes a starter can burn up a battery, in fact a starter motor can catch fire if they are overheated. No joke. That's why the starter solenoid switch was invented. To create the load from low battery power that a starter needs to turn over a large gas combustion engine. Starter motors take a lot more power to run than you think. A starter is a very high amperage armature. "

It's not a capacitor.
It's just a way to switch the current without the current having to go through the ignition key. More like a relay. And doesn't protect the battery, it protects the ignition switch. It's role is to ensure high current can pass from the battery to the starter, with an ignition switch being 40 wire feet away (or more) and without having to run heavy duty wires (that cost lots and weigh lots) from battery to switch to starter.

A capacitor stores energy. A relay just switches current on and off.

cimplexsound · 01-06-2018, 11:52 PM

Quote:

Originally Posted by Dav L

"Hold the STOP button in for about 15 seconds before attempting to start. This forces the fuel pump to run to make sure it has fuel in the carb bowl."

Interesting...did not know that.

Holding in on the stop button seems to have no effect of any kind when the generator is not running. I wired a a three way switch to manually prime the line before starting the genset. Below is my video of how this generator was running as of this morning.

https://youtu.be/6mdHagevAr8

twinboat · 01-07-2018, 12:04 AM

A solenoid is a remote controlled, high amp capacity, relay. It uses a low amp electromagnatic coil to close a 300 amp set of contacts.

A " starter mounted " solenoid does the same thing AND pulls the starter motor pinion gear into the engine ring gear.

A small engine, like a 4000 watt generator starter, rairly use starter mounted solenoids. The pinion gear moves up a coarse thread to engage the flywheel.

cimplexsound · 01-07-2018, 12:18 AM

Quote:

Originally Posted by twinboat

A solenoid is a remote controlled, high amp capacity, relay. It uses a low amp electromagnatic coil to close a 300 amp set of contacts.

A " starter mounted " solenoid does the same thing AND pulls the starter motor pinion gear into the engine ring gear.

A small engine, like a 4000 watt generator starter, rairly use starter mounted solenoids. The pinion gear moves up a coarse thread to engage the flywheel.

I know. Cheap manufacturing too. You look a nice starter motor, then you pull it off the generator and are horrified at the level of today's cheap manufacturing. 😱 I've checked this model however. My owners manual says The Emerald Genset 1 uses a regular bendix gear starter verses a pinion gear starter which is used in the Onan Marquis series. Because the flywheel rides between the engine and the power stater armature under a protective cover. However even the bendix starter is plastic now. How they think plastic will last in a steel engine setup is more than I can figure out. Just plain crazy. All rebuilds, nothing is new anymore. We live in an age of plastic cars and plastic machines. Again cheap, cheap manufacturing.

THenne1713 · 01-07-2018, 12:33 AM

Additionally the Winter LEVER on the air filter opens the door for air that has passed over the cylinder fins but it gets to the air filter from a paper/ foil tube that has to be properly installed in the BACK of the air filter box... but it is out of sight and MAYBE NOT connected???????, so OIL, AF, Electrical connections, spark plugs, fuel quality (age/ moisture/ water?)