Hi all,
Sorry about the long title, this is my first post here and I have a few concerns about my 1973 65hp Johnson. (edit- I shortened the title and started a new thread on my reeds.) I must say that I've been impressed with the amount of knowledge on this forum, and I've learned much using the search. Here's a little background on my issue:
This will be the 5th season for me running this engine. It has been a consistently good runner, and always starts right up. The boat is used mostly for water sports, so quite a bit of idling followed by wide-open acceleration. The boat has had a good idle, but occasionally after a few minutes of idling, the boat will die when we go to "hit it" as though it has loaded up. However, even though the engine is plenty warm, it starts back up best with a touch of choke. This is the part that has me confused, as it seems as though the engine is plenty rich, I've never experienced any sneezing, and I don't need to choke the engine too long during cold starts, but it seems as though it usually starts back up best with the choke. This is true if the engine has died on initial acceleration or if the engine has been shut off for a few minutes. On the occasion that the engine dies on acceleration, it seems like it runs better after "clearing it out" by advacing the idle for a few seconds with the cold start lever/idle advance.
Since this problem didn't occur all the time it didn't bug me too much, but last summer I towed the boat up to North Idaho, and it seemed like it compounded the issue. I'm used to running at sea level, and the lake we were in was slightly over 2000' IIRC, so a little bit of change, but not so much that I thought it would be a hinderance. However, at altitude, I could not get the boat to idle for an extended period at all without advancing the idle lever. When the engine was placed back down to a normal idle, it would last about 15-30 seconds before pooping out. I figured I'd be running extra-rich with the altitude, but here again it would need some choke to start back up. Also when we were getting going, we really had to ease in the throttle, as the normal "hitting it" would kill it every time. Once we were going, the boat ran great, but any idle operations would not work like normal. We were in North Idaho for a week, and later in the week the issue seemed to get a bit better when the day temps dropped from 100 to 70 (a little more air density?)
So, I guess my question is, am I jetted a bit rich, as I suspect (poor running at 2000') and if so, why does using the choke help to get the thing running when it dies? Or... is it lean and this is why I need to ease into WOT?
The next part goes like this:
My coils were starting to get cracks in them, and after reading about the hazards this can cause to the power pack, I went ahead and replaced my coils last week. While I was ordering these up, I also ordered a set of Boyesen 133 reeds, as I do get a bit of fuel/oil coming back though the carbs, especially at WOT. I'm hoping to get to the reeds in the next week or two, but was wondering a few things about the installation:
(Edit- removed the orifice questions to start a new thread.)
Could my above idle-at-alt issues have been partially caused by my old reeds?
Lastly, I've read some contradicting information on my carburators, and from what I've heard some of the manuals even have it wrong on this. I guess I won't know until I take them off, but I'm expecting to just have the idle orifice in the top of the carb, and understand that the only other "jet" is the high speed fuel one. I'm not tearing into the carbs as they were rebuilt not-to-to long ago, but I will replace the idle orifice as nessesary. I haven't taken one out yet, but I'm expecting it to be a #31. If people think otherwise, or if I should have a second idle circuit thingy as I've read somewhere about something, please let me know. (Edit- just came in from taking the airbox off, and it looks like I don't have the extra off-idle circuit, and my top idle orifice was a #31)
I realize I've filled this post with quite a few questions, but any help or ideas would be greatly appreciated.
Thanks in advance!
Since this is my first post, here is the boat:
Sorry about the long title, this is my first post here and I have a few concerns about my 1973 65hp Johnson. (edit- I shortened the title and started a new thread on my reeds.) I must say that I've been impressed with the amount of knowledge on this forum, and I've learned much using the search. Here's a little background on my issue:
This will be the 5th season for me running this engine. It has been a consistently good runner, and always starts right up. The boat is used mostly for water sports, so quite a bit of idling followed by wide-open acceleration. The boat has had a good idle, but occasionally after a few minutes of idling, the boat will die when we go to "hit it" as though it has loaded up. However, even though the engine is plenty warm, it starts back up best with a touch of choke. This is the part that has me confused, as it seems as though the engine is plenty rich, I've never experienced any sneezing, and I don't need to choke the engine too long during cold starts, but it seems as though it usually starts back up best with the choke. This is true if the engine has died on initial acceleration or if the engine has been shut off for a few minutes. On the occasion that the engine dies on acceleration, it seems like it runs better after "clearing it out" by advacing the idle for a few seconds with the cold start lever/idle advance.
Since this problem didn't occur all the time it didn't bug me too much, but last summer I towed the boat up to North Idaho, and it seemed like it compounded the issue. I'm used to running at sea level, and the lake we were in was slightly over 2000' IIRC, so a little bit of change, but not so much that I thought it would be a hinderance. However, at altitude, I could not get the boat to idle for an extended period at all without advancing the idle lever. When the engine was placed back down to a normal idle, it would last about 15-30 seconds before pooping out. I figured I'd be running extra-rich with the altitude, but here again it would need some choke to start back up. Also when we were getting going, we really had to ease in the throttle, as the normal "hitting it" would kill it every time. Once we were going, the boat ran great, but any idle operations would not work like normal. We were in North Idaho for a week, and later in the week the issue seemed to get a bit better when the day temps dropped from 100 to 70 (a little more air density?)
So, I guess my question is, am I jetted a bit rich, as I suspect (poor running at 2000') and if so, why does using the choke help to get the thing running when it dies? Or... is it lean and this is why I need to ease into WOT?
The next part goes like this:
My coils were starting to get cracks in them, and after reading about the hazards this can cause to the power pack, I went ahead and replaced my coils last week. While I was ordering these up, I also ordered a set of Boyesen 133 reeds, as I do get a bit of fuel/oil coming back though the carbs, especially at WOT. I'm hoping to get to the reeds in the next week or two, but was wondering a few things about the installation:
(Edit- removed the orifice questions to start a new thread.)
Could my above idle-at-alt issues have been partially caused by my old reeds?
Lastly, I've read some contradicting information on my carburators, and from what I've heard some of the manuals even have it wrong on this. I guess I won't know until I take them off, but I'm expecting to just have the idle orifice in the top of the carb, and understand that the only other "jet" is the high speed fuel one. I'm not tearing into the carbs as they were rebuilt not-to-to long ago, but I will replace the idle orifice as nessesary. I haven't taken one out yet, but I'm expecting it to be a #31. If people think otherwise, or if I should have a second idle circuit thingy as I've read somewhere about something, please let me know. (Edit- just came in from taking the airbox off, and it looks like I don't have the extra off-idle circuit, and my top idle orifice was a #31)
I realize I've filled this post with quite a few questions, but any help or ideas would be greatly appreciated.
Thanks in advance!
Since this is my first post, here is the boat:
IIRC my idle while in forward gear is normally around 700rpm, but looking in the repair manual I see that for my 65hp engine, I'm actually supposed to adjust the idle in reverse gear. I'll have to give that a shot.