yanmar gm30 problem

[poodle57irene]

i have a problem starting the engine. white smoke, then eventually starts. once started is fine all day. no smoke. next morning same problem, new injectors, fuel tank drained, fresh deisel, new filters, restrictor elbow repaired., used decarboniser agent in fuel. any ideas anyone. have reached a block
last year we had contaminated deisel which was drained and fresh put in with agent added.

many thanks

[NOLAsailing]

It might be unrelated to fuel. Check your battery connections and, if your batteries are old, consider replacing them.

It can also be an air leak. You may want to be sure that your bleed point connectors are as tight as they need to be, if this started just after replacing fuel and fuel filters.

Also, most Yanmars want some throttle when you start them up.

[SteveInMD]

White smoke mean unburned fuel. This is probably a result of the amount of cranking you are doing before it starts. If you motor had glow plugs I would say there may be a problem with that system, but I'm pretty sure it's a direction injection motor and has no plugs. Have you had the compression tested?

[SteveInMD]

A fuel system air leak is a possibility, but I would expect that it wouldn't idle well with an air leak. Once running does it idle down nice and smoothly, or does it shake and or run rough?

[capn_dave]

but, I am going to do it anyway. Just how much white smoke comes out when starting the engine? Will the smoke go away after it warms up?
It is not unusual for an engine to pour forth white smoke on initial startup. It is unburnt fuel. I would also consider doing a compression check. If it has low compression allot of fuel can get into the cylinders. after th engine starts the rich fuel mixture comes out as white smoke.


Fair Winds

Cap'n Dave

[jrd22]

Our 3GM is also difficult to start at times, and will put out a fair amount of white smoke. About half throttle seems to work best, and after cranking for a few seconds we pull it back to idle and it ususally starts right up. I read here in another thread that they pull the engine stop out and crank the engine for a few seconds and then push the stop in while cranking and it starts. I'm going to try that as the weather gets colder. We also had a slight leak at the final fuel filter, replaced the o-ring and it improved starting.

Good luck, John

[NOLAsailing]

One other thing, if it doesn't start fairly quickly, close the intake seacock before you keep cranking and open it as soon as the motor is running. This is important.

[badsanta]

Question? If you pull the engine stop, does this not cut off the fuel? I dont understand how that would help, other than lube things up. But If it works, oh well.

[poodle57irene]

hi to everyone
thankyou all for taking the time to reply.
we have tried tightened all air bleed nuts, filter, jubilee clips on fuel lines back to the tank. we have replaced batteries, new manifold and restrictor elbow,bottom half of injectors renewed.
engine runs smooth at idle once initially started
we had the injectors renewed because of the fuel contamination problem, but prior to this no problems.
it takes about one minute to start with considerable white smoke, then starts fine each time after with no smoke and runs smoothly.

how could i detect an air leak? in case this is the problem.

many thanks
john

[arf145]

badsanta, the purpose of cranking some with the fuel cut off is to heat up the cylinder, head, etc. through compression before introducing fuel. And it does get things lubed before they have much load on them.