Ed Clark
Active Member
So, the second sea trial with The Beast was a complete bust. This was conducted on Saturday, 12/7/24. To stay on topic, you will recall that ventilation aka cavitation of one engine is the problem that this thread is attempting to address. The rest of this post is simply a sob story that you'll learn nothing from although you might find it humorous from a comic tragedy point of view. Just joking. Only saying that if you read the balance of this you aren't going to learn a lot about the subject topic.
So, here goes. As background, I should tell you that unlike SDC_MI's vessel, mine is a project boat that has been considerably used and abused by previous owners. We do have in common the ventilation issue. So, the plan that I was supposed to execute from my previous post was to order and install a new aftermarket "thru-hull fitting" on the starboard engine. I did receive same and it was beautiful in construction and dirt cheap. I pulled the s pump, driveshaft and boot only to discover that, well, it would be a waste to time to install the new fitting as the original seemed to be in perfectly serviceable condition. So, I reassembled everything paying special attention to ensure the boot/friction ring assembly were making a good fit. By the way, I did use an alternate boot that I had laying around in the parts pile.
You may recall that on sea trial one I also had a problem with the port engine in that it would pull to around 3,000 rpm then immediately bog as if running out of fuel and drop back to idle. So, I had refurbished the port carb with a kit and tested the pop off to 24 (should have been 26 minimum per spec) and called it a day in that department. I ran both engines dry for around 4 minutes and all seemed OK. I didn't want to bother running them on muffs again, but as you shall discover, perhaps I should have.
So, the night before the sea trial the temps had dipped to the mid twenties. When I went out to check the boat again before towing to the river I discovered that the forward/reverse cables (one for each engine) and the steering cable were frozen and their control handles couldn't be moved. In retrospect, this make perfect sense as the point the cables exit the stern is submerged iin operation and are bound to take on some water. However, it was a new one on me. I fear I got a little violent with trying to free them up including trying to defrost them with a heat gun. Well, nothing seemed to work so I tentatively wrote off the sea trial for the day.
In the afternoon, the sun had been beating down on The Beast for a couple or three hours and I decided on a whim just to see what was going on. Lo and behold, the frozen cables had defrosted. Really getting late in the day at this point but I was chomping at the bit so I ran through my quick checklist, hooked her up and an hour later I was at the river launch.
The day had warmed to about 40 at this point but the temps were already starting to drop for the day. There was only one other trailer at the launch. One of the die hard bass guys no doubt. Being alone, I used the old tie a lead rope to the pier walkway, back up and stop aggressively to launch the boat technique. I then coaxed the boat to the end of the pier and tied both bow and stern to cleats. The plan was to run the darn thing under power on both engines while statically tied to the pier. This as a safety precaution before I commenced a run on the river from which there might literally been no return depending on engine performance.
Ah, I must pat myself on the back for my wisdom such as it is. Read on. So, I board and start both engines. Both are idling very nicely and I allow them to warm for about 10 minutes or so while I revel in just what a great day this is going to be. Not! Read on. The first malady encountered was that the starboard engine would not rev. Why? Broken throttle cable. Probably my fault for jacking things around in their frozen state. But, doesn't matter. One engine out of the picture but that's the reason you have two, right?
Lo and behold I notice that the port engine is leaking water out of the top engine cover. I had been warned about this by the previous owner but had not witnessed it myself so wrote it off as him being a dope. Now we know who the real dope is. Not to be deterred since I had a functioning bilge pump (I hope) and I was bound and determined to run at least one engine on the day. Not! Same old bogging issue as before. As I tried to increase rpm's above idle, it would spin up a bit then bog right back down.
Crap! Well that's almost the end of the story, but not quite. Of course there was no way to load the boat by coaxing it back on the trailer with the aforementioned lead rope. Fortunately(?), I had foreseen this eventuality and had provisioned myself with a pair of sneakers for lower leg submerged work in icy waters. Good thing I did as there was a coating of mud on the ramp cleverly hidden under the waterline.
Anyway, the next day was warm enough and I had a gasket set in stock so I undertook to replace the cylinder head o-rings. This didn't go too badly. However, it was noted that while the bores and pistons looked fine, there was some distortion in the water jacket area of the rear cylinder. Also, the replacement gasket set provide one round o-ring as a replacement for the OEM square o-ring. So, if you had to guess, where would you say I got an immediate leak upon restarting the engine on muffs?
So, here's the path forward. The port engine is coming out for an eventual rebuild. I have a spare shortblock that shows good compression but I have never heard run that will be going asap. Also, of course, a repair to the starboard throttle cable is in the plan as well. Recall, that the whole point of this thread is to find a solution to the ventilation aka cavitation issue on the starboard engine.
Even colder weather coming as well as Christmas at this point. Still, I'm pumped to conduct sea trial number three. Best guess is the end of December for the next report. Sooner if weather permits and the back-up engine actually runs when installed.
So, here goes. As background, I should tell you that unlike SDC_MI's vessel, mine is a project boat that has been considerably used and abused by previous owners. We do have in common the ventilation issue. So, the plan that I was supposed to execute from my previous post was to order and install a new aftermarket "thru-hull fitting" on the starboard engine. I did receive same and it was beautiful in construction and dirt cheap. I pulled the s pump, driveshaft and boot only to discover that, well, it would be a waste to time to install the new fitting as the original seemed to be in perfectly serviceable condition. So, I reassembled everything paying special attention to ensure the boot/friction ring assembly were making a good fit. By the way, I did use an alternate boot that I had laying around in the parts pile.
You may recall that on sea trial one I also had a problem with the port engine in that it would pull to around 3,000 rpm then immediately bog as if running out of fuel and drop back to idle. So, I had refurbished the port carb with a kit and tested the pop off to 24 (should have been 26 minimum per spec) and called it a day in that department. I ran both engines dry for around 4 minutes and all seemed OK. I didn't want to bother running them on muffs again, but as you shall discover, perhaps I should have.
So, the night before the sea trial the temps had dipped to the mid twenties. When I went out to check the boat again before towing to the river I discovered that the forward/reverse cables (one for each engine) and the steering cable were frozen and their control handles couldn't be moved. In retrospect, this make perfect sense as the point the cables exit the stern is submerged iin operation and are bound to take on some water. However, it was a new one on me. I fear I got a little violent with trying to free them up including trying to defrost them with a heat gun. Well, nothing seemed to work so I tentatively wrote off the sea trial for the day.
In the afternoon, the sun had been beating down on The Beast for a couple or three hours and I decided on a whim just to see what was going on. Lo and behold, the frozen cables had defrosted. Really getting late in the day at this point but I was chomping at the bit so I ran through my quick checklist, hooked her up and an hour later I was at the river launch.
The day had warmed to about 40 at this point but the temps were already starting to drop for the day. There was only one other trailer at the launch. One of the die hard bass guys no doubt. Being alone, I used the old tie a lead rope to the pier walkway, back up and stop aggressively to launch the boat technique. I then coaxed the boat to the end of the pier and tied both bow and stern to cleats. The plan was to run the darn thing under power on both engines while statically tied to the pier. This as a safety precaution before I commenced a run on the river from which there might literally been no return depending on engine performance.
Ah, I must pat myself on the back for my wisdom such as it is. Read on. So, I board and start both engines. Both are idling very nicely and I allow them to warm for about 10 minutes or so while I revel in just what a great day this is going to be. Not! Read on. The first malady encountered was that the starboard engine would not rev. Why? Broken throttle cable. Probably my fault for jacking things around in their frozen state. But, doesn't matter. One engine out of the picture but that's the reason you have two, right?
Lo and behold I notice that the port engine is leaking water out of the top engine cover. I had been warned about this by the previous owner but had not witnessed it myself so wrote it off as him being a dope. Now we know who the real dope is. Not to be deterred since I had a functioning bilge pump (I hope) and I was bound and determined to run at least one engine on the day. Not! Same old bogging issue as before. As I tried to increase rpm's above idle, it would spin up a bit then bog right back down.
Crap! Well that's almost the end of the story, but not quite. Of course there was no way to load the boat by coaxing it back on the trailer with the aforementioned lead rope. Fortunately(?), I had foreseen this eventuality and had provisioned myself with a pair of sneakers for lower leg submerged work in icy waters. Good thing I did as there was a coating of mud on the ramp cleverly hidden under the waterline.
Anyway, the next day was warm enough and I had a gasket set in stock so I undertook to replace the cylinder head o-rings. This didn't go too badly. However, it was noted that while the bores and pistons looked fine, there was some distortion in the water jacket area of the rear cylinder. Also, the replacement gasket set provide one round o-ring as a replacement for the OEM square o-ring. So, if you had to guess, where would you say I got an immediate leak upon restarting the engine on muffs?
So, here's the path forward. The port engine is coming out for an eventual rebuild. I have a spare shortblock that shows good compression but I have never heard run that will be going asap. Also, of course, a repair to the starboard throttle cable is in the plan as well. Recall, that the whole point of this thread is to find a solution to the ventilation aka cavitation issue on the starboard engine.
Even colder weather coming as well as Christmas at this point. Still, I'm pumped to conduct sea trial number three. Best guess is the end of December for the next report. Sooner if weather permits and the back-up engine actually runs when installed.
