[Gnirts]

Hi,We've recently got a Mariner 150 engine approx 10 years old and it doesnt seem to like cold starting very well. To get the engine ticking over without stalling it requires nearly full hand throttle.In addition to this, when on very low revs for slow speed it has a habit of occasionally stalling requiring a restart, again with the hand throttle raised to get it going.Can anyone post a trouble shooting guide or some advice on what to look at to identify the problem ?Thanks

[Keith Buchanan]

First thing to do is a simple compression test. If they are close on all pots new spark plugs and high tension leads are the order of the day. Plugs and leads are 90% of the problem in my experience. Either you will have cured your problem or you will have eliminated a whole bunch and post back for further tips..Good luck Keith B... keep it simple.

[Gnirts]

OK. Spark plugs will be changed tomorrow when they arrive so at least we can eliminate that. Will post back in a few days when i get back if it hasnt cured it.Thanks for the reply.

[KCLOST]

If you have to advance the throttle that much to get it or keep it running, it sounds more like a fuel issue....Go ahead and replace the plugs, but it may be time for a carb rebuild.... May be your low speed jets clogged up...Are you priming the bulb prior to starting it cold?

[Gnirts]

Yep bulb is primed and hard before starting attempts.I noticed the fuel filter looks to be 90% full of rubbish - could this be affecting the starting or isnt it a problem?

[KCLOST]

Yes, the filter can restrict fuel flow....replace it and retest...

[dingbat]

With a motor that age it's time to change out the fuel pump diaphragm also. Low fuel pressure could be a reason why it runs OK when you open up the throttle a little ways

[Gnirts]

We think its about 10 years old but cant find a serial number on there to attempt to ID the year.All thats written on the top of the engine block is "V150" and on the actual cylinder: 87976AS / 3400On the starter motor area, 50-7714?? 10 3 90Changed the spark plugs today and cleared the fuel filter and it seems to start better, no hand throttle needed and generally idles OK but dropped out once or twice.

[ronmold]

serial # should be on the tilt/swivel bracket, starboard side

[Gnirts]

OK the serial number reads:0D056850Ive looked on http://www.marinshopen.se/ and think it might be a 1991 V150 or V150 Magnum 2. Is this correct? If its the right year i'll order a maintenance manual for it.