Mercury Sailmate 4hp problem

[BogMonster]

Ever since I got it I have not been at all convinced that the Merc 4hp I bought as an aux is working properly. My old Suzuki 6hp on the old boat used to start on 2 or 3 pulls even after sitting for ages, if it had been running the same day it would start first pull every single time and idle smoothly.

Compared to the Suz, the Merc has always been a pig to start and never idled smoothly. Now it doesn't idle at all but more to the point when I tried it this afternoon it wouldn't even start.

It had about 1/4 tank of fuel and the engine has what appears to be a mechanical lift pump on the side of the engine. This doesn't appear to lift any fuel - with the tank 1/4 full, I took the pipe off the carb and pulled and pulled and pulled and F all came out. I am sure on the Suzuki if you did this you got a fairly steady stream of fuel after a couple of pulls and I think that's what should happen. There is no manual priming pump as far as I can see, and presumably an engine should start with 1/4 tank of fuel.

So I filled the tank right to the brim and then fuel came out ... and it started.

I assume the lift pump is probably knackered and has probably never worked - anybody agree with this?

Having got it running it is the same as it has been the last couple of times I have used it - it simply will not idle. Once you get it going (which is a bit of a chore often needing 10-15 pulls) it will idle fast on choke but even when warm it won't idle at all - you have to have the throttle at about the "fast idle" position or above, or it will stop.

It's only on its second tank of fuel since new (total run time maybe an hour to an hour and a half) and both times it has been filled from a clean can with fresh fuel so contamination in the carb should not be a problem unless it has been there from the factory. Having said that when I first got it I sat it on my engine stand and filled it with fuel which promptly all ran out the bottom of the engine as the fuel pipes weren't connected, so it may be a Monday morning job from top to bottom

Any thoughts on the above please? It seems like similar symptoms to my Suzuki when I did have fuel contamination issues with that after a couple of years but this should not be unless it is a problem from the factory.

I'm obviously about to email the supplier with the above info as it's still under warranty, and I haven't picked anything to bits yet as I want their view first, but any thoughts would be welcome as I will have to fix it myself anyway. At the moment it's not a hell of a lot of use as an emergency aux if it won't start and run properly

Ta

[samt]

are you running off the integral tank or internal tank? If integral, because of the abnormal shape, the engine can have difficulty picking up fuel when the tank is low, especially when moving up and down on the sea.

[BogMonster]

Running off the engine's internal tank. I've not tried the external tank yet as I have nowhere to strap it down in the boat. I hadn't thought about it but the lift pump must be essential when you are using the external tank as in most cases it would be much lower than the engine.

[samt]

I'd try running it on the external tank. I have 25 of these of these engines on a hire fleet, and have serviced and PDI'd many more. Never had issues with the fuel pumps.

Speak to your dealer first, (assuming it came from a UK dealer via barrus) barrus are always supportive

[chewy]

Uncle Al should be able to help you.

[BogMonster]

I don't really want to have to run it off the external tank - that was one reason for getting the Sailmate to have an internal tank so I have an emergency power source immediately available without having to couple up an external tank or have it rigged all the time. If it can't suck from the internal tank (fuel level about 2 inches below the pump) surely the external is going to be worse?

What sort of pump is it anyway - diaphragm? impeller? you can't tell from looking at the outside.

It wasn't moving up and down it was parked in my yard on the trailer but the engine had been stored tilted up for a couple of weeks since I last used the boat - but again I would have thought that tilting an engine into the normal position and then starting it was not an unreasonable thing to expect to do without problems.

I've emailed the dealer I bought it from so will hopefully get a reply tomorrow anyway and see what they say.

Can you download electronic workshop manuals for these engines anywhere? Handy to know which jets are where if I have to strip the carb which I guess I will have to for the idling issue anyway.

[uncle al]

hi bogmaster
your problem seems fuel related, unfortunutly for you i am on holiday untill next thursday, (but good for me) if you would like to send me your e-mail address to alan.surman@barrus.co.uk with your obm serial number i will send you an exploded view of the carb if that will help you.
merry christmas and a happy new year
regards
uncle al

[uncle al]

sorry bogmonster i got your name wrong ,old age and digit trouble

[uncle al]

sorry bogmonster i got your name wrong ,old age and digit trouble

[BogMonster]

Thanks Al that would be great. I will have to look up the serial number on the engine as I don't have it here but will do that later. I bought it this year so I expect it's a 2010 model.