1983 Volvo Penta md17c

[scottrgrewe]

I have a 36 hp, 3 cylinder Volvo with estimated LOW hours, like 1k. It’s about 35 years old however.
I’ve done routine maintenance, change oil, oil filter, fuel filter, impeller, have spare alt, etc.
It is a little hard starting, a little Smokey, seems to be a bit of fuel or oil in exhaust, and sometimes the rpms vary without changing throttle.. as if it doesn’t like to be at 1800, it goes up to 2 k or down to 1600 and steadys..

I plan on some extended voyaging next fall. I was wondering if anyone had any advise on the specific engine, observations I’ve made, or on spares to carry (other than previously mentioned) also, any other maintainence that should be looked at, IE raw water cooling systems etc.

[Compass790]

I'd be looking at a compression test for a start as low compression can cause hard starting + it's smokey so either rings or valve guides are worn. Just because it's low hours doesn't mean the engine is ok. the rev hunting i'd be suspecting the governor or fuel injection pump. may just need cleaning.Get a workshop manual before you attempt anything on those parts.
this is just general diesel advice as i'm not familiar with volvos so better if you get some engine specific advice from an md17c owner.
There are a few threads on spares to take if you search on CF

[Compass790]

Oh sorry maybe injectors mite be causing the smoke. Blue smoke is oil.

[Cheechako]

It's time to have the injectors tested and rebuilt anyway. DO that first, it's not too expensive if you can remove them etc.

RPM varying sounds like a starving fuel issue. Possible things for that:
-Fuel filter getting clogged (on engine and possibly external one too)
-Air in fuel, possibly from a line leak (sucking in) or air in a filter housing.
-Vents on hull sides for vent line are clogged (critters do this sometimes) While running for a while, take the fill cap off... is there a vacuum there?
-Pick-up tube end in bottom of tank is clogged. (how old is this fuel? has it ever been polished?)

Other possibilities for starting issues:
-bent push rod on one cylinder, this can happen and you may not even know it. It can even come off the rocker arm and lay to the side. You could be running on 2 cylinders. This creates fuel or oil in the exhaust too from that cylinder. Remove the rocker cover and look to see.
-Possible head gasket problem allowing oil or etc into the cylinder.

[Lepke]

In the US it's illegal to leave a sheen on the water. If I was going on an extended trip, I'd find out why I have a sheen. It could be injectors, valve guides, or rings & cylinders. The rpm hunting is the governor.

Now would be the best time to solve potential engine problems.