The '81 E70ELCIM on my Sportscraft 15' has been giving me some problems. The boat and motor is new to me, only about 4 weeks, and I'm new to boating. The carbs were rebuilt last July to the tune of $700. Isn't that high?
The problem began as bogging down on WOT, not being able to get up on plane only making about 8 or 9 MPH. Giving a short press on the ignition key would add a bit of speed and another press would add a little more until the boat was up on plane. I ran Seafoam in a couple of tanks of gas and then the problem changed to the motor wanting to die after about 3/4 throttle.
Haven't done compression check as I don't have guage yet.
Yesterday, giving a good visual check looking for leaks in fuel lines, I spotted a small (about 5" hose) coming from the bottom of exhaust manifold but was not connected to anything. It looks like it connects to the bottom of the air silencer. I think it is item #49 on the Crowley Marine intake manifold parts diagram for an '81 70HP Evinrude.
I connected the hose to the bottom of the air silencer which seemed right. Took the boat out for a run and after running it for about 20 minutes at WOT the motor seemed to perform normally.
My questions are these:
1. Could that hose being disconnected have given me my previous problems?
2. I noticed when I removed the air silencer that the two very bottom screws were missing, probably because they are lower then the lip of the engine base and not easy to reinstall. According to the OMC drawing it looks like these screws are above the lip but I can't figure how mine could have become lowered. Is it important that these two screws be installed?
3. The bottom part of the air silencer gasket had broken away and was also missing. Is this gasket important for the operation of the motor? (Obviously it has a function, but I'm surprised that the shop which worked on the carbs didn't replace it.)
I thank you in advance for any input from the experts in the forum. I've enjoyed reading through the forum - you guys really know your stuff!!
The problem began as bogging down on WOT, not being able to get up on plane only making about 8 or 9 MPH. Giving a short press on the ignition key would add a bit of speed and another press would add a little more until the boat was up on plane. I ran Seafoam in a couple of tanks of gas and then the problem changed to the motor wanting to die after about 3/4 throttle.
Haven't done compression check as I don't have guage yet.
Yesterday, giving a good visual check looking for leaks in fuel lines, I spotted a small (about 5" hose) coming from the bottom of exhaust manifold but was not connected to anything. It looks like it connects to the bottom of the air silencer. I think it is item #49 on the Crowley Marine intake manifold parts diagram for an '81 70HP Evinrude.
I connected the hose to the bottom of the air silencer which seemed right. Took the boat out for a run and after running it for about 20 minutes at WOT the motor seemed to perform normally.
My questions are these:
1. Could that hose being disconnected have given me my previous problems?
2. I noticed when I removed the air silencer that the two very bottom screws were missing, probably because they are lower then the lip of the engine base and not easy to reinstall. According to the OMC drawing it looks like these screws are above the lip but I can't figure how mine could have become lowered. Is it important that these two screws be installed?
3. The bottom part of the air silencer gasket had broken away and was also missing. Is this gasket important for the operation of the motor? (Obviously it has a function, but I'm surprised that the shop which worked on the carbs didn't replace it.)
I thank you in advance for any input from the experts in the forum. I've enjoyed reading through the forum - you guys really know your stuff!!