Motor hard to pull start

[xparte]

Are you guys getting your manuals anywhere specific online?

I've been looking around the closest thing I could find (that was public/free) was a 40HP 4 stroke one unfortunately. Found a few more sites but they all led to a site that req registration/credit card. I don't mind paying if it's the right manual but thinking these might be just clickbait.

[VictorOscar]

Hi,

I have a Mercury 40Hp motor that hadn't been used in about 4-5mths. I tried to start it the other day but it's strangely hard to pull and it comes out in like sections each pull.

It's in neutral (tried putting it into gear and back a few times) and new petrol but it's still doing it. Finally after about 40 pulls and getting the rhythm right, I was able to start the motor. Once the motor started it ran just fine and left it on for a while. It's just the starting mechanism/pull rope that seems like it's getting jammed or stuck.

Able to start the motor now after a few pulls if I can get the rhythm right for a straight pull (not that easy) but can't get rid of the tension.

Tried spraying oil all around the area (& flywheel?) to see if that would help but it didn't.

Here's a short video of what happens: https://drive.google.com/file/d/1jUE...ew?usp=sharing

Does anyone know what could be wrong or where to start looking for the problem?

Appreciate any advice. Thanks!

That looks like the 40hp Jap Merc 2 stroke (ie. a Tohatsu)?

The motors have a lot of compression and if you can't build up enough speed when pulling the rope the compression of each cylinder will stop the rope coming out in one go.

It took me a while to get the start up procedure correct but now I can start it from cold in 2 or 3 pulls, you've got to get a lot of speed up with the pull though.

[Fed]

What motor is it?
Merc (tick)
2006 (fail) Mercury don't work on Year Models

Serial Number?
2 stroke or 4 stroke?
Number of cylinders?
Carb or Fuel Injected?

I might have a manual that could help you.

[xparte]

That looks like the 40hp Jap Merc 2 stroke (ie. a Tohatsu)?

The motors have a lot of compression and if you can't build up enough speed when pulling the rope the compression of each cylinder will stop the rope coming out in one go.

It took me a while to get the start up procedure correct but now I can start it from cold in 2 or 3 pulls, you've got to get a lot of speed up with the pull though.

I'm actually not sure. It's branded Mercury but I heard that all Tohatsu motors under 40 or 50HP were actually made by Mercury.. or was it the other way around?

I went and re-tested the motor this afternoon and I was actually able to start it after just a few pulls. In saying that though, I pulled extra hard as I realise that's what's needed now but after turning it off, I was able to restart it on a single pull and it didn't seem so heavy as previous. Today was the first day I tried restarting after the first use a few weeks ago but it definitely seemed easier. I don't really know much about compression but can the level drop after using the motor for a bit? Could that be a reason why it's a bit easier now?

What motor is it?
Merc (tick)
2006 (fail) Mercury don't work on Year Models

Serial Number? 0N061501
2 stroke or 4 stroke? 2 Stroke
Number of cylinders? I'm not sure, can I tell from the motor?
Carb or Fuel Injected? Carb I think? It's not DFI if that's what you mean?

I might have a manual that could help you.

This is the serial label on the motor: https://d.pr/i/yO26gB . Hopefully you can work out which motor I have from my answers. If you do have the manual, would really appreciate a copy Thanks!

[Fed]

Can't help you.

[VictorOscar]

I'm actually not sure. It's branded Mercury but I heard that all Tohatsu motors under 40 or 50HP were actually made by Mercury.. or was it the other way around?

I went and re-tested the motor this afternoon and I was actually able to start it after just a few pulls. In saying that though, I pulled extra hard as I realise that's what's needed now but after turning it off, I was able to restart it on a single pull and it didn't seem so heavy as previous. Today was the first day I tried restarting after the first use a few weeks ago but it definitely seemed easier. I don't really know much about compression but can the level drop after using the motor for a bit? Could that be a reason why it's a bit easier now?




This is the serial label on the motor: https://d.pr/i/yO26gB . Hopefully you can work out which motor I have from my answers. If you do have the manual, would really appreciate a copy Thanks!

Yeah that's the Merc Jap 40hp - good motor.

I wouldn't think your compression would have dropped significantly over a few weeks.

More than likely, it's just the regular use the motor has been getting recently that is making it easier.

You mentioned you didn't use it for 4/5 months initially? You may have just had to blow the cobwebs out of it.

I always make a habit to run mine once a month, after time the fuel evaporates and leaves the oil which makes starting it more difficult.

[xparte]

More than likely, it's just the regular use the motor has been getting recently that is making it easier.

You mentioned you didn't use it for 4/5 months initially? You may have just had to blow the cobwebs out of it.

I always make a habit to run mine once a month, after time the fuel evaporates and leaves the oil which makes starting it more difficult.

Yep it was sitting untouched for about 4-5mths but I tried it again this morning and it's definitely gotten easier so I think you may be right about the regular use lately.

I think it's at the point where I'm fine with the amount of energy needed to pull start it. It started from cold on the 2nd pull today and subsequent starts went on 1st pull.

Hopefully it's not just 'cause I'm on land. First run I had on it (where I had issues), it took 30mins tied to the wharf getting rocked by boat wash, a lot of patience and arm muscle to finally get it going. Silly me was too confident of it starting that I didn't test it first the day before.

[scottar]

You did pump the fuel primer and use choke I assume.

[VictorOscar]

Yep it was sitting untouched for about 4-5mths but I tried it again this morning and it's definitely gotten easier so I think you may be right about the regular use lately.

I think it's at the point where I'm fine with the amount of energy needed to pull start it. It started from cold on the 2nd pull today and subsequent starts went on 1st pull.

Hopefully it's not just 'cause I'm on land. First run I had on it (where I had issues), it took 30mins tied to the wharf getting rocked by boat wash, a lot of patience and arm muscle to finally get it going. Silly me was too confident of it starting that I didn't test it first the day before.

Sounds like you have the starting procedure under control and that you just flooded the motor the other time.

If it is starting on land, it'll be fine on the water, though it won't hurt to start it the night before or leaving your house for the ramp until you're confident in the motor again.

Another note, I bought mine new and found it wasn't running as well as I thought it could.

I took it to my usual mechanic who I know can tune carby's/timing etc and got him to tune it up - helped with the starting.

[xparte]

You did pump the fuel primer and use choke I assume.

I did. I think the main issue was that I just couldn't get a good pull on the rope the first time out as it was just too hard. That and the motor had been untouched in 5mths.

On the successful pulls the motor did splutter a bit and then did start for a few seconds before turning off. Thinking back now, I did change the petrol to new petrol but there would've been old petrol in the pipes still? Maybe once that cleared out it kicked in?

Sounds like you have the starting procedure under control and that you just flooded the motor the other time.

If it is starting on land, it'll be fine on the water, though it won't hurt to start it the night before or leaving your house for the ramp until you're confident in the motor again.

Another note, I bought mine new and found it wasn't running as well as I thought it could.

I took it to my usual mechanic who I know can tune carby's/timing etc and got him to tune it up - helped with the starting.

I probably did flood it with so many attempts the first time! I'm a bit more confident now with the easier starts today. Will do the once a month run in future if I don't use the boat for a while as well.

Might bring it up with the mechanic next time I get a service and have him test it just to double check.

-


Thanks to everyone for the advice. Appreciated!

[scottar]

Opinions vary, but my personal thoughts are to idle the engine with the fuel line disconnected until it starts to run out of fuel. The only exception is with oil injected engines. This does away with any fuel issues in regard to things getting gummed up in my experience.

[Dignity]

One thought, is your throttle completely in the lowest setting, I find it needs to be slightly on otherwise it will struggle to start.

[Moonlighter]

Every pull start 2 stroke I have had has its own particular technique to start.

I always remember a early 1970’s Johnson 25hp we had back in the early 80’s. The guy we bought the boat/motor feom told and showed us how to start it when cold:

1. Prime the fuel bulb up nice and firm.
2. Pull choke lever all the way out. Full choke.
3. One hard pull on the rope. It would never start first pull, but ....
4. Push choke half way back in, and pull the rope hard again. It would fire and run
5. Quickly push the choke all the way back in to keep it running, and give it a little throttle, not much just a touch.

If I followed this procedure it was guaranteed to work 9/10 times. The 10th time it would need a second pull with the choke half in. When it was warm, it would start all day first pull with no choke.

We always pulled the fuel line off and ran the carby dry when we flushed the notor at the end of the day.

Fast forward many years........

A couple years ago a mate and I bought a tinny from a deceased estate, and it had a late 80’s Johnson 25 on it. The motor design had hardly changed.

I bet him I could start the motor with no more than 3 pulls of the rope.

I used exactly the same procedure we used on the old one, and even though this motor hadnt been started for 6 months, with a fresh tank of fuel, it kicked on the second pull of the rope and fired up and ran on the third.

This exact procedure may not work on your Merc, but there will be a way that your motor likes to be started when it is cold, and when you fugure it out, remember it, because it will reliably start every time if the same procedure is used.

[xparte]

Opinions vary, but my personal thoughts are to idle the engine with the fuel line disconnected until it starts to run out of fuel. The only exception is with oil injected engines. This does away with any fuel issues in regard to things getting gummed up in my experience.

I read that too and will start to do that if I think I won't take the boat out anytime soon. I also grabbed some stabiliser so will use that if needed too.

One thought, is your throttle completely in the lowest setting, I find it needs to be slightly on otherwise it will struggle to start.

Never tried that but will remember that, thanks! I think it's starting ok now, just got to make sure the rope stays easy to pull as I think that was my biggest obstacle.

This exact procedure may not work on your Merc, but there will be a way that your motor likes to be started when it is cold, and when you fugure it out, remember it, because it will reliably start every time if the same procedure is used.

You're right and I'm starting to think I figured out my motor. I tried starting it again today and it seems to be going good now. Never tried the half choke but will give that a go if it doesn't fire after a couple of pulls.

I was always under the impression that the choke did a similar job to just turning up the throttle but apparently not!

[Moonlighter]

Haha!

No the choke reduces the air supply and enriches the fuel/air mix. Makes a completely cold engine easier to start. But engines dont like to run with full choke left on.

You could give the method I outlined a try and see if it works for your motor. Maybe it will, or some similar variant will work.