Mariner 135hp two stroke issue

Yardstick · 15 July 2024, 12:03

Hi all,

I've got a Mariner 135hp two stroke from around 2000 which has an intermittent issue. The engine starts and runs fine, pushing the boat to over forty knots easily however after a period of running if I stop the engine it won't restart for ten minutes. The battery is good and turns the engine over without issue, the fuel is good and the filter is good.
The engine was recently serviced and the mechanic said the engine was in pretty good condition but didn't know why the engine would fail to restart after stopping.
Any ideas where I should start?
Cheers.

Pikey Dave · 15 July 2024, 14:40

Quote:

Originally Posted by Yardstick

Hi all,

I've got a Mariner 135hp two stroke from around 2000 which has an intermittent issue. The engine starts and runs fine, pushing the boat to over forty knots easily however after a period of running if I stop the engine it won't restart for ten minutes. The battery is good and turns the engine over without issue, the fuel is good and the filter is good.
The engine was recently serviced and the mechanic said the engine was in pretty good condition but didn't know why the engine would fail to restart after stopping.
Any ideas where I should start?
Cheers.

If you pump the fuel bulb whilst trying to start it, does it help?

User name · 15 July 2024, 14:58

If you spray some EasyStart into the intake when it's refusing to start, and it then fires up you'll narrow your issue down to fuelling rather than ignition/electrical.

Peter_C · 15 July 2024, 15:42

Most likely fuel related but not 100%. When it acts up try opening the throttle fully into clear flood mode and see if it starts. If so it is flooded. <Most likely scenario as fuel evaporates in about ten minutes.

If not then reverse and add fuel by pulling on the choke. Should that not work add more fuel via an Ether based starting fluid. (Stuff with top end lube is good.) If it starts it is lack of fuel. Doubtful as carbs wouldn't magically fill up on their own in ten minutes of doing nothing.

Then there is the electrical side of things. Do the carbs have a solenoid for fuel shutoff? Is it getting spark when it isn't starting?

paintman · 15 July 2024, 16:11

Begin by checking for a good spark when you get one of these 'refusal to start' episodes.
And that the plugs aren't wet.

If you have a good spark & the plugs are dry then a squirt of Easy Start is a good call. If the engine fires & tries to run on that then it points to a fuel delivery issue.

Yardstick · 15 July 2024, 17:46

Cheers lads,

Pikey Dave, I tried squeezing the bulb whilst trying to start the engine. The bulb was firm and squeezing had no effect.

User Name, I didn't actually think of that. I'll borrow a can from work and try it next week.

Peter C & Paintman, again something I haven't checked is the spark. What I hope to do next week is replicate the problem by running the engine on load in the loch then stopping the engine once we're safely tied up. I seem to remember these things being recommended on the forum for testing spark

Thanks for the great advice

paulbrown22 · 15 July 2024, 18:16

I love those Accuspark testers on my classic cars and highly recommend them! They do almost double the length of the spark plugs though, and sometimes I find the HT leads on outboards are a bit short. Hopefully they fit on yours though, and I certainly find them a super easy way of checking for spark to the top of the plug without taking anything apart. A "spark" on these doesn't necessarily mean the electrode is sparking properly in the cylinder if the plugs themselves are knackered though, but a much quicker first test!

Peter_C · 15 July 2024, 19:45

Pulling a plug on land and inspecting would be a good call. Black on the center part means rich. White means lean. Tan/Brown is just right.

Yardstick · 16 July 2024, 06:53

Thanks for the advice guys. I've ordered a set of Accuspark testers and a can of Easystart to narrow it down to either a fuel or electric issue.

whiskylee · 16 July 2024, 08:29

If you rule out fuel issues, CDI electronics have an excellent troubleshooting guide.
Google CDI troubleshooting, and select your Engine

Yardstick · 16 July 2024, 11:34

Thanks for the heads up Whiskylee, I've just downloaded the pdf

Nos4r2 · 16 July 2024, 12:11

Dumb question, but you're not using the choke while restarting while hot are you?
I met a guy a few years ago that'd put hundreds into a techs pocket to try and resolve a hot starting issue on a Yam 90 and all it was, was he kept flooding it with the choke...

Yardstick · 16 July 2024, 16:53

Hi Nos, nah not a dumb question at all. All the boats I've owned previously have been diesel and I'm now trying to get my head around fault finding on petrol outboards so any advice is gratefully received.
No, didn't try starting with choke as the engine was up to temperature.

Pikey Dave · 16 July 2024, 23:22

Quote:

Originally Posted by Yardstick

Hi all,

I've got a Mariner 135hp two stroke from around 2000 which has an intermittent issue. The engine starts and runs fine, pushing the boat to over forty knots easily however after a period of running if I stop the engine it won't restart for ten minutes. The battery is good and turns the engine over without issue, the fuel is good and the filter is good.
The engine was recently serviced and the mechanic said the engine was in pretty good condition but didn't know why the engine would fail to restart after stopping.
Any ideas where I should start?
Cheers.

just for clarity, does the problem only present itself if you stop the engine? if you keep the engine running & give it beans, will it run all day until you switch it off, & then it won't start? what happens if you give it a good run & then come back to tickover, and then power up? Is it purely a starting issue when warm? When you try to start, is the engine turning over & not firing, or is it completely dead, no solenoid click or warning beeps?

Yardstick · 17 July 2024, 12:43

Hi Dave, The engine runs like a champ all day at all revs from tickover to wot. The problem only occurs when the engine is warm and I turn the engine off. The starter engages and turns over fast and freely but still fails to restart until around 10 mintues has passed.

The first time it happened we were fishing the west side of Kerrera and I decided to turn the engine off as the drift looked pretty good. Turned the key to get going after the drift and it wouldn't restart so fired up the back up engine and headed for home. On the way back I tried the engine again, which restarted without issue. Once started it ran like a champ again with the odd sprint of 40 knots in sheltered areas.

It's more irritating than anything else.

paintman · 17 July 2024, 19:07

I wonder if the residual heat is vapourising the fuel at the engine - possibly in the pump or in the line - & the pump is unable to pull fuel from the tank until it's cooled down.
Something that used to happen on some Triumph cars which wouldn't restart after a fast run & then stop - much the same as your issue.
Some were Police cars which I would think would have been embarassing to say the least.

If it works on the Easy Start then it's fuel.
If it doesn't it might be something electrical again not liking the heat. Some Rover V8s had an issue with the ignition amplifier which saw Land Rover come up with a remote mounting.

Be interesting to know what happens!

ETA +1 for CDI's troubleshooting & another +1 for their speedy service when I needed a trigger & stator for my own 135hp.

Peter_C · 17 July 2024, 19:27

Quote:

Originally Posted by Yardstick

Hi Dave, The engine runs like a champ all day at all revs from tickover to wot. The problem only occurs when the engine is warm and I turn the engine off. The starter engages and turns over fast and freely but still fails to restart until around 10 mintues has passed.

The first time it happened we were fishing the west side of Kerrera and I decided to turn the engine off as the drift looked pretty good. Turned the key to get going after the drift and it wouldn't restart so fired up the back up engine and headed for home. On the way back I tried the engine again, which restarted without issue. Once started it ran like a champ again with the odd sprint of 40 knots in sheltered areas.

It's more irritating than anything else.

Did you try setting the throttle to full throttle while cranking the engine? This causes a lean condition to help start a flooded engine, by removing the vacuum that would otherwise be pulling more fuel thru the jets. It can take 20+ seconds sometimes to clear a severe flood.

A1an · 17 July 2024, 20:46

im not familiar with the 135, does it have an auto choke/enricher for cold starting?

User name · 17 July 2024, 21:04

Quote:

Originally Posted by Yardstick

Hi Dave, The engine runs like a champ all day at all revs from tickover to wot. The problem only occurs when the engine is warm and I turn the engine off. The starter engages and turns over fast and freely but still fails to restart until around 10 mintues has passed.

The first time it happened we were fishing the west side of Kerrera and I decided to turn the engine off as the drift looked pretty good. Turned the key to get going after the drift and it wouldn't restart so fired up the back up engine and headed for home. On the way back I tried the engine again, which restarted without issue. Once started it ran like a champ again with the odd sprint of 40 knots in sheltered areas.

It's more irritating than anything else.

While on the subject of checking the simple things, Is the tank vent functioning ok?

Peter_C · 17 July 2024, 23:39

Quote:

Originally Posted by User name

While on the subject of checking the simple things, Is the tank vent functioning ok?

I would imagine a tank vent not being open would cause the engine to stall while driving it and not restart. Speaking from experience...and it was an easy fix 30 seconds later after stalling as the tank was kinda shrunken.

Unless you get into modern emission standards and freezing conditions older boats with built in tanks do not have sealed fuel tanks.