Thanks all
Official answer from Yanmar: I had talked to a different dealer and he got with Yanmar and this is what they said. "Officially: you need a 3". Unofficially: 2" will work with 12' of pipe and a water muffler up to 55 hp." They also said that going with a 2" may void the warrenty depending on who was making the decision. Volvo: Because Volvo uses glow plugs, that elimiated them. So I figured a brand new Yanmar, even without a warrenty, is better then a rebuilt yanmar with only a 90 day warrenty. Decision made: So, this morning I went down to the repair shop and put in an order for a new 40 hp yanmar. Here is the kicker: The repair shop, who deals Yanmars and Volvos, called Volvo and they said if it was there filter that blew on a volvo engine, they would replace the engine. Evidently Yanmar doesn't feel the same because I would think he would have called them too. In anycase, I don't have the filter anymore as proof so that's all a mute point anyway. Damn! rebuilding it myself... I used to be a diesel mechanic in the army a good 15 years ago but never rebuilt one. I once rebuilt a gas engine and when finished it had a knock that I couldn't find the cause so I ordered a remanufactured engine and vowed never to try again (I spent months trying to find that knock and fix it).
My engine was all rusty from the Antigua flood. The boat was stored on the hard during the off season in Trinidad. A friend came down and helped with recommissioning until my wife could get off work. We launched. He was aboard the boat. I was in the dingy. He headed out to the anchorage and slowed and stopped. He said the engine quit. I climbed aboard and dropped the hook. There was no oil on the dipstick. He said the alarm was going off but he didn't know what it meant so he kept going! Grrrr. The 'drip-pan' was a mess. I added oil. We started it. It started right up but oil was pouring out of the side of the engine. A hidden oil line next to the starter had rusted through. My regular fogging with Boeshield couldn't reach it even if I knew it was there. So we pulled the line. What a bitch in the tropics. We went to the boat yard shop to get it repaired. They said they couldn't. I looked in the phone book for dealers. There were FOUR Yanmar dealers in Trinidad. I called the first one. I told him what I needed. He said he had one and would deliver it to the boat yard for free. He was at the bar with the line before we finished our first beer. Then we bought him a beer. I paid him with my Visa debit $240 TT. That's $40.00 U.S. Still have the receipt in my wallet. We had the engine puring in an hour. When I rebuilt the engine I found that the third main bearing had been stripped of its babbitt. But the engine worked perfectly for the next three years and home across the Caribbean. The bearing is kept in the chart table. And the crankshaft was PERFECT. And I rebuilt it myself at one third the cost of a new one. Next time I'll replace. Did you try to start it after it quit? I think your 'mechanic' is handing you a line. Want to hear my exhaust elbow story? What's that? 