Trouble Starting my Yanmar 1GM

[bullrunner]

I have a 1983 27' Hunter with a Yanmar 1GM. I'm having trouble starting. It will take 5-10 minutes before the engine starts but once starting it does/will run. I've taken a fuel sample from the primary filter and the fuel is pretty dark and in bad shape. I've treated the tank with Startron Fuel tank cleaner and then tried using an electronic fuel transfer pump to bring fuel from the tank through my primary filter and back into my fuel tank to try and clean the fuel but to no avail. I've tried hooking the fuel line directly into a standby diesel can with clean fuel and still have trouble starting. I've also noticed that when attempting to start I sometimes get white smoke coming out of the air intake. I've been told this is most likely a valve problem. Can anyone help me figure out where to even begin? Thanks

Ted

[jones2r]

Diesels will run on all kinds of gunk, except water. Since it eventually starts and runs, it may not be a fuel issue. The symptoms suggest a sticking intake valve, which will compromise compression. Take a compression test; if the results are low, you have the reason for its not wanting to start. Of course, valve problems are not the only cause for low compression. If introducing top cylinder lube (Marvel oil) to the fuel mix tends to alleviate the problem, then you probably do have a valve problem, and the cylinder head should be pulled and rebuilt.

[bullrunner]

Thanks for the info jones2r. I will do that and see what I find. I appreciate your help and hopefully I won't have to pull the cylinder head

[Goodnewsboy]

While you are at it, have your fuel injector checked out/rebuilt by a competent diesel shop.