1999 mariner 40hp help needed

[tommyturbo]

Hello im new to boats and outboards and starting to wish id not brought this engine...

Got this engine a few weeks ago and has been a nightmare from day 1. Basically noticed it was misfiring and was getting hard to start. Once out the water it was clear the top cylinder was misfiring. Did a compression test and it was 135psi on both, then a spark test that showed its had a poor spark on top. Had a guy do the test but its now missing on both. The engine run ok but now its terrible and wont idel. To make things worse it now stopped peeing water after using the muffs.

The engine is a ex rnli 40 2 stoke pull start with some weird extra piping and a carb heater thing. Im guessing the fault is electric and im struggling to understand the electric system it uses. Im in the south east near oxford if anyone can help or recommend someone. Thanks tom

[Festinghouse]

do you have a multimeter? if not, then buy one. then google 'testing stator, trigger, switchbox on mariner 40' you should be able to find all the tests to carry out, pay real close attention to the wire colours and readings to expect and when. all this testing can be done by yourself for just the cost of a meter. you should find that you will end up with a much better understanding of the engine once youre done! my guess would be the cdi/switchbox failure but you need to run the test. once you get your head around the electrics you will find them to be quite simple really.

[Nos4r2]

Get it in to Mike at Redline Outboards in Abingdon. Can't speak highly enough of him.

[rossymtb]

What year Mariner are you talking about?
Does it run on points? Have you cleaned them?
How about earth ponts have you cleaned all of them?

Ive had a mega amount of trouble with the few engines i have had,
Merc 110 9.8hp
Yamaha 20hp 80's

Both where misfiring and both were down to old points and condensors.

I also noticed a big difference when i replaced the plug caps with new ngk ones

*Misread its 1999 so should be on electronic ignition which doesn't use points or condensor*

Does it still spark on the top cylinder? Might be that the coil has now burned out,
Have you tried new spark plugs. Make sure they are gapped correctly aswell, Also worth checking that the fuel filters are clean

[tommyturbo]

Cheers for the advice, will find my dads multimeter tomorrow. Been reading a few bit on google thanks to u. It's a pull start engine so will that matter for testing the wires? Or does it have need to be running?

It's a single carb 2 cyl 2 stroke?

Thanks again.

[Nos4r2]

It's electronic ignition and you'll need a manual for it before a mutlimeter is much use.

[uncle al]

there was a problem with the earths on those obms remove, clean to shiny metal,push pull the connecters on the earth wiresif there is no movement refit and make sure that they are tight.Myself and the service manager used to do the final inspection on them before they left the distributer here in bicester

[uncle al]

If you want to put some pictures on here I will endever to tell you why, and what they were for.