Mariner 40 EFI - Have I missed something?

[winja]

Hi all.

I am new to boating but I have tried my best to fix my problem without having to hassle anybody on here by going through all the posts I could find with regard my engine type and then carrying out checks and replacing parts as best I could but I have now reached the limit of my already severely limited ability.

The problem I have is that after runnng at wot for a couple of minutes, the engine coughs and splutters and will only settle down if I return the throttle to the neutral position and then slowly increase it again.

The engine is a Mariner 40hp EFI four stroke outboard. The boat is a 16 foot open cuddy type. Both boat and outboard where made in 2006.

To my knowledge the engine and boat where left standing for the last 18 months. The boatyard salesman told me that the previous owner only used the boat 5 or 6 times from new. He was selling it for him.

It appears that the engine has never been serviced.

This is what I have done so far .....

Disposed of old fuel and put clean fuel in.
Replaced fuel tank and fuel hoses with new, including primer bulb.
Checked the anti-syphon valve on tank, appears ok.
Inspected and cleaned water separator filter, outboard fuel filter and the in-line fuel filter.
Replaced all 3 spark plugs.
Drained the VST (No visible signs of contamination).

There is a good stream of water from the pee hole and there are no alarms going off. Although, i did have an alarm go off the first time we put the boat in the water. It was a constant alarm and the engine revs appeared limited but after switching the cut out switch off and on again the alarm stopped.

Is there anything anbody can think of that I may have missed?

Or, is it time to admit defeat and take it to a dealer who can run it on his computer? I have tried to avoid this as the boat is in a harbour and is a hassle to get out and also the dealer keeps saying " Oooo, tut tut, not this week mate, we are very busy blah blah"

Any suggestions will be gratefully welcomed.

 

[Traceyh]

Re: Mariner 40 EFI - Have I missed something?

Is it always the same, a couple of minutes, then sputter, the throttle down, then good to go again for a couple of minutes? That sounds like a classic case of a fuel tank vent not open far enough, or somehow restricted. Have you tried to squeeze the primer bulb while it is sputtering? Have you viewed the primer bulb while sputtering to check for collapsed bulb indicating a vacuum on the system.

 

[Faztbullet]

Re: Mariner 40 EFI - Have I missed something?

Sounds more like a fuel stravation, several possible items are: mechanical fuel pump diaphram,filter on high pressure pump in VST, sticking float in VST.

 

[winja]

Re: Mariner 40 EFI - Have I missed something?

Hi Tracyh.

Thanks for your reply.

I did suspect the fuel hoses and primer bulb and replaced them both. When the spluttering occurs I had my friend pump the bulb but it made no difference. I also checked the fuel tank vent and made sure it was open.

 

[winja]

Re: Mariner 40 EFI - Have I missed something?

Sounds more like a fuel stravation, several possible items are: mechanical fuel pump diaphram,filter on high pressure pump in VST, sticking float in VST.

Thanks for the reply mate.

I have suspected a fuel problem all along but once I get to the VST I am afraid that, with my mechanical knowledge and engineering skills, or rather the lack of, I would end up making a pigs ear out of a silk purse. Not good!

I know that I should'nt expect some kind of magic formula for rectifying this problem but I thought it would'nt hurt to get some independent assessments to make sure I had'nt missed something silly, so thankyou for your time but I can see myself having to bite the bullet and take it to a dealer. :redface:

 

[winja]

Re: Mariner 40 EFI - Have I missed something?

Well, I bit the bullet and took the boat to a dealer who serviced the water pump!!! Yeah, water pump. It may well have needed servicing but thats not what I asked him to do for gods sake.

I asked him if he checked the fuel pressure and he said no, it only needed a new high pressure fuel filter and all would be cool.

?200 later I put the boat back in the water, left the harbour, gave it some stick and guess what? Yup, same old story.

So I thought I would have a go at trying to fix the problem myself. I downloaded a service manual and started going thru the fuel system from top to bottom.

All seemed ok, no blockages anywhere or anything untoward.

I checked the float valve in the VST and cleaned out the bowl but found nothing that would explain my problem.

I then stripped the mechanical fuel pump and although the diaphragm appeared to be intact, there was a rather worrying scoring mark inside the unit around the edge of the alluminium casing.

I would like to ask if anybody feels this could be an issue before I lash out on a new pump. I would also be extremely grateful for any other ideas that could be causing my distress.

I have a mechanically minded friend who is hoping to get over at the weekend with his fuel pressure testing kit so I may have more information then but for now I would welcome any input with regard the mechanical fuel pump.

Thanks for your time.

 

[Timestep]

Re: Mariner 40 EFI - Have I missed something?

You need to get a proper Mercury approved mechanic to put it on a "Digital Diagnostic Terminal" then all will become clear. It could easily be the thermostat or something simple. The terminal will also reveal the true history of your engine, the number of hours and the breakdown of those hours into rev ranges.

Here in Devon there are two people that will come to my pontoon or to my house/drive/barn with the Terminal.

?200 seems a lot for a water pump rebuild as well!

BTW I lived in Portreath in the 60's when it was a coal port.

Regards

Dave

 

[winja]

Re: Mariner 40 EFI - Have I missed something?

Hi Dave, thanks very much for your reply.

The dealer that did the water pump service is an approved Mariner dealer and they did do a diagnostic check but they tell me that the software they have is not the full Mariner software nor do they have the facility to print off the results!

I was just talking about the thermostat being a potential problem with a friend of mine. It led us back to the first time we put the boat in the water after I bought it when it had laid unused for around 18 months by the previous owner.

The overheat alarm went off for around 3 minutes then suddenly stopped after we reset the cut off switch and restarted the engine.

This was confirmed by the dealer when he ran a diagnostic check at the time they replaced the water pump kit. Looking at the invoice they also removed and cleaned the thermostat so they must have been suspicious that this may have been the problem.

I am going to Falmouth today so I will pick up a new thermostat and see how we go from there.

I am a bit dubious about returning to the same dealer until I have tried my best to rectify the problem myself, so I would like to thank you for your input and I will let you know how I get on.

BTW It is a beautiful calm day out of Portreath today and I am desperate to get back in the water whilst the weather is like this as there cant be many days like today left!

 

[Timestep]

Re: Mariner 40 EFI - Have I missed something?

Without the proper software they are useless; totally useless!

The makers of your boat supply the engines and they are a couple of miles south of Falmouth, call in and ask them who has the proper equipment?

I had a guy come to my house, rebuild the water pump and fit a new thermostat for ?90.00, OK I did get the parts earlier and that was just labour. But I now have a history of my engine.

How long have you lived in/near Portreath?

Regards

Dave

 

[winja]

Re: Mariner 40 EFI - Have I missed something?

Guess you are talking about Allen marine down in Maenporth. Yeah, that's where I bought the boat. They where selling for someone else. I contacted them and they said they would get a mechanic to call me but I am still waiting 6 weeks later.

Neither of the two Mariner agents in my area have the proper software. One told me it was too expensive. I mean, how can they call themselves service agents when they havent the equipment to do a service?

I believe there is another agent in Fowey so I am considering calling them.

Quick question about the thermostat. Did your engine suffer the same symptoms as mine before you replaced it?

As to your question re. Portreath, I have been here since 1990 and love the place. The harbour entrance can be a bit hairy though! Particulary when your outboard cuts out right when you don't need it to!

Thanks again.

Paul.

 

[Timestep]

Re: Mariner 40 EFI - Have I missed something?

You should ask Allen Marine who has the equipment, then you can call them directly and ask?

I had the 30hp that was all but the same, now I have the 60hp. However the warning buzzer sounded at the time the engine overheated and went into limp home mode.

Does your warning buzzer give a strong bleep when you first turn the ignition on?

I was in Portreath from about 1961 to 1963, can you still get to Lady Bassets Bath?

Regards

Dave

 

[winja]

Re: Mariner 40 EFI - Have I missed something?

Hi Dave.

I have just taken the thermostat out and it looked knackered.

Did the hot water test and it is seized solid.

Im off to Falmouth now to have a word with the so called agent.

Will get a new one and test the boat later.

 

[Timestep]

Re: Mariner 40 EFI - Have I missed something?

Well, well!

Does your warning buzzer give a strong bleep when you first turn the ignition on?

Dave

 

[winja]

Re: Mariner 40 EFI - Have I missed something?

Well I took the stat to Falmouth and they tested it in hot water and it opened. Typical. Darn thing wouldnt open for me here. I told him I must have loosened it.

Just waiting for high tide so we can drop the boat back in the water and test it out.

Oh, and yes, there is a loud beep when I first turn the ignition on so the alarm appears to be working as it should.

Will keep you posted.

Paul.

 

[Timestep]

Re: Mariner 40 EFI - Have I missed something?

Hi Paul

OK, I think it's time for a proper service engineer!

Regards

Dave

 

[winja]

Re: Mariner 40 EFI - Have I missed something?

Hi Dave.

As it turned out it was too rough to take the boat out, (Was flat calm this morning ), so we just reversed down the slipway and tested it whilst on the trailor.

All seems well. Ran it for ten minutes at close to full power and no signs of any problem.

Fingers crossed that it is fixed at last.

As a footnote I was speaking to a guy in the RNLI this afternoon. He said that their inshore boat uses two mariner 40's the same as mine and they had a similar problem which they traced to a fault on the kill switches which they have now disconnected. Maybe take a look at that if the problem returns.

I will hopefully get back in the water tomorrow for a run out to sea. Will keep you posted.

Thanks for all your help mate.

Paul.

 

[winja]

Re: Mariner 40 EFI - Have I missed something?

Yippeeeeeeeeeeee! I think I've cracked it!

Took her out today, ran her for over an hour and she never missed a beat.

I cant be sure as to what the actual fault was as I checked and cleaned quite a few things in the last couple of days, but one thing I havent mentioned is that a Mariner service engineer told me that they had the same engine as mine in their workshop and they where having very similar problems and that they had come to the conclusion that it was being caused by a fuel vapour lock because of an airlock in the water pipe that goes from the bottom of the fuel cooler into the engine casing. I ran water through the engine using earmuffs for a few seconds and disconnected this water pipe at the fuel cooler to try to dislodge any air lock. I may be mistaken but there seemed to be an increase in pressure of water from the tell-tale after this.

Any way, hopefully I have solved my problem and would like to thank all on here who have taken the time to answer my post, particularly Dave. And yes Dave, Lady Bassets bath is still apparently there albeit full of rocks from where the local council blew up part of the cliff a few years back.

 

[Timestep]

Re: Mariner 40 EFI - Have I missed something?

On a sunny low tide winter day, I'll come over and inspect the bath!

The thermostat isn't really up to salt water. Don't know why, on my 30efi that had the same size thermostat, I fitted a new one every year, but one year I needed two! Just carry a 10mm socket to take it out if it fails. I did this last time...........

Regards

Dave

 

[Jeep Man]

Re: Mariner 40 EFI - Have I missed something?

Well, I bit the bullet and took the boat to a dealer who serviced the water pump!!! Yeah, water pump. It may well have needed servicing but thats not what I asked him to do for gods sake.

I asked him if he checked the fuel pressure and he said no, it only needed a new high pressure fuel filter and all would be cool.

?200 later I put the boat back in the water, left the harbour, gave it some stick and guess what? Yup, same old story.

So I thought I would have a go at trying to fix the problem myself. I downloaded a service manual and started going thru the fuel system from top to bottom.

All seemed ok, no blockages anywhere or anything untoward.

I checked the float valve in the VST and cleaned out the bowl but found nothing that would explain my problem.

I then stripped the mechanical fuel pump and although the diaphragm appeared to be intact, there was a rather worrying scoring mark inside the unit around the edge of the alluminium casing.

I would like to ask if anybody feels this could be an issue before I lash out on a new pump. I would also be extremely grateful for any other ideas that could be causing my distress.

I have a mechanically minded friend who is hoping to get over at the weekend with his fuel pressure testing kit so I may have more information then but for now I would welcome any input with regard the mechanical fuel pump.

Thanks for your time.

Mercury/ Mariner fuel pumps of that era do have a problem of binding at half and three quarter throttle, and it runs normal at low speed. Generally it shows up after 4 or 5 years of service. Newer style pumps have a design modification. This would explain the scarring.

 

[winja]

Re: Mariner 40 EFI - Have I missed something?

Thanks for that Ray.

If the problem returns I will look at servicing the pump with replacement parts.

Cheers for now

Paul.