mercruiser 165 idling rough

[michael s.]

i got a few questions about my engine. it's a 1978 mercruiser 165 in a renken 19 ft bowrider i just changed the water pump this week and started the engine it will start ok but you have to give it about 1/4 throttle to keep it running. when i back it down to neutral it lobes and coughs and dies . should i check the timing first, distributor,wires or carb? or do i need to check them all i just bought the boat 2 weeks ago and it seemed to run ok on the hose at the guy's house where i bought it but now seems to be running rough any help would be greatly appreciated

 

[Bondo]

Re: mercruiser 165 idling rough

should i check the timing first, distributor,wires or carb? or do i need to check them all i just bought the boat

Ayuh,... At the Very Least you should Check Everything,...
Fluid levels,. Filters,.. Oil levels... Igntion,..

In the Adults Only section you can find a Boatload of Info,.. including the factory Service manuals...

 

[ziggy]

Re: mercruiser 165 idling rough

i'd think start with a compression test. make sure ya are working with something that's got hope. then i'd move on to a minor tuneup. if ya've not already replaced these items for your spring turneup, then, yep, cap, rotor, condenser, points, plugs (be sure to check for proper gap), wires, maybe. clean fa. if yer workin with already replaced this season items. then i'd go to dwell first, then timing. dwell effects timing. if that still ain't got ya hip, i'd do the fuel filer in the fuel pump and check the filter screen at the carb inlet. next it'd be a toss up between checking the fuel system prior to the carb. ie anit siphon valve, fuel pump pressure, maybe performing some of the fuel system checks in dons' fuel system dia. problem thread in the adults only sticky. or, go directly to the carb. rebuilding the 2gc is about as easy as carb rebuilding goes i'd think. after that...

Ayuh,... At the Very Least you should Check Everything,...

yep. a new to you boat, anything and everything is suspect i'd think. a good place to get an idea about what everything is is in the summerization/winterization thread in the adults only sticky...