View Full Version : Yanmar 1 cyl 8hp hard to start

12-10-2006, 02:47 PM
"My faithful yanmar barely started and then did not start again after warmed up. It seemed like lots of sooty black smoke when running,then I shut it down for a little while and tried to start nothing but misery! This catalina 27 has been in the family for 15 years and I had the best luck with it.Any Info would be welcome,thanks ,Nathan"

12-10-2006, 04:31 PM
"post model #. if its an older boat, could be YSE or YSM ? (horizontal cylinder) or 1GM (vertical cylinder) also, does it have a proper exhaust system, or made up system. (plumbing pipe, lagged) ?"

12-10-2006, 07:39 PM
"I thought it was a YSB 8 it is horozntal,it does have proper exhaust system"

12-11-2006, 12:02 AM
"ok, YSB. been a few years since I've worked on one. will refresh myself in am. still have books on it. reason I asked about exhaust is catalina made their own. had a habit of plugging up. classic symptom was hard start, and sooty exhaust. will check book, and post tommorrow. S."

12-11-2006, 11:32 AM
"prime suspect is exhaust mixing elbow. over time, they fill with carbon, narrowing exhaust passage. have also seen deteriorated hoses collapsed internaly. if it can't breathe, it can't run. next I would check injector. to test properly, needs to go to shop. most diesel shps can pop test. call around. You can do a rudimentry test on Your own, though. remove injector, reconnect fuel line, and turn over. should spray a fine mist, about 15 degrees wide, with no streams, or drips.(IMPORTANT- there is a pre combustion chamber beneath injector, that will shoot out like a bullet. remove, or contain it!!!) also, shut off water intake before cranking more than 30 seconds, as You could fill exhaust lift, and engine. check and post. S."

12-11-2006, 11:56 AM
"Thanks,I will check hose and passages for buildup of carbon.Give me a few days to check things out the boat is 60 miles away. Nathan"

Capt William Myersl
12-14-2006, 03:32 PM
The first rule of diesel repair is anytime you have a problem, check the fuel first, change filters, you may have water, of bio sludge in the fuel. Before you do anything else draw some fuel and look at it. Have you ever pumped the water off the bottom of the tank? Opened the tank and cleaned it?"

12-15-2006, 08:22 PM
"cap'n, I agree completely. check filters, etc. first. worked for a yanmar dealer years back in San Diego, and saw a lot of these engines. a lot of catalinas too. very common there. and plugged exhaust was very common cause of soot. but, always check basics first. good point."

01-23-2007, 02:03 PM
"Thanks for all of your input! I just sold the boat as is.Thank you,Nathan."

New Owner
05-02-2008, 01:18 PM
What do you do if it sucks in water through exhaust?

05-14-2009, 03:32 PM
"NIce to have found this site , I just bought myself a ysm 8 today in parts but all overhauled so that will be a nice thing to put together again, I was wondering in what kind of boat to put it , to what size do they perform best, has anyone have suggestions , I still have to buy a boat with it,"

05-15-2009, 12:52 AM
hi i have a 1gm10 yanmar and its rated at 9hp and it pushes my yacht really well my yacht is 23foot and weight approx 2500 pounds not fast but steady and reliable