MikeCaldwell
Cadet
- Joined
- Apr 20, 2015
- Messages
- 14
8 months ago a friend gave me a dead sitting in the back yard for years it is an Evinrude 15hp 15804B 1978. Long time motocrosser and engine builder 2/4 strokes, a meticulous perfectionist with engines and computer systems.
I didn't plan on rebuilding everything but one thing led to another and I couldn't help rebuild the whole thing, replacing everything I could which included new .030 Pistons/cranks/rings (And the Barrels bored by a pro) all the parts sat on the shelf since 1977, I have an engine builder who bored it out and handled the specs as he did with my race bikes. I had fun painting it hippy colors and taking my time over the months replacing everything I could.
I finally got it started, I believe my problem is the damn carb, cleaned it, and will be replacing the float, etc in a day or 2 I got a complete rebuild kit for the carb and waiting for a new fuel/pump hose and connectors. I get it started, it might even idle for a bit, I been trying not to hammer the throttle too much being new pistons but it revs fine and stays running for maybe 3-5 minutes at most then slowly comes down in idle until it dies and nothing kicks it back up. Then I have to wait a bit and I try again and it does the same thing. I didn't have anything tiny enough to push through the low-speed idle holes I may try again when I get the kit. I am assuming its not anything ignition, it kicks right up, got gas on both plugs no problem. I suspect a leak of the carb gasket or hose not pumping gas and leak which I will replace the carb contents and hose and connector next. Sounds great, the kept the lower prop off for now, it's loud ;-) However I wonder, our 2 strokes on the motocross bikes, expansion chamber is the key to running fast and right. Does the lower part act as any kind of expansion chamber / back presser to keep this running? I couldn't upload the bigger video starting it, I will do a new one. Evinrude 15hp 15804B 1978 Complete rebuild 3x over bore.
Thanks for any help.
I didn't plan on rebuilding everything but one thing led to another and I couldn't help rebuild the whole thing, replacing everything I could which included new .030 Pistons/cranks/rings (And the Barrels bored by a pro) all the parts sat on the shelf since 1977, I have an engine builder who bored it out and handled the specs as he did with my race bikes. I had fun painting it hippy colors and taking my time over the months replacing everything I could.
I finally got it started, I believe my problem is the damn carb, cleaned it, and will be replacing the float, etc in a day or 2 I got a complete rebuild kit for the carb and waiting for a new fuel/pump hose and connectors. I get it started, it might even idle for a bit, I been trying not to hammer the throttle too much being new pistons but it revs fine and stays running for maybe 3-5 minutes at most then slowly comes down in idle until it dies and nothing kicks it back up. Then I have to wait a bit and I try again and it does the same thing. I didn't have anything tiny enough to push through the low-speed idle holes I may try again when I get the kit. I am assuming its not anything ignition, it kicks right up, got gas on both plugs no problem. I suspect a leak of the carb gasket or hose not pumping gas and leak which I will replace the carb contents and hose and connector next. Sounds great, the kept the lower prop off for now, it's loud ;-) However I wonder, our 2 strokes on the motocross bikes, expansion chamber is the key to running fast and right. Does the lower part act as any kind of expansion chamber / back presser to keep this running? I couldn't upload the bigger video starting it, I will do a new one. Evinrude 15hp 15804B 1978 Complete rebuild 3x over bore.
Thanks for any help.
