thanks guys. The impeller i took a pic of i bought from a boat dealer locally. Had to give them the engine serial number and i probably should have checked the number that was stamped on it.
But....Good news!! (and some not so good, but not really bad i guess)
First, it appears my overheating issue is now resolved. Replaced the entire RWP with another new VP unit (surprised its not painted, but that's for some other time) and finally took it to the ramp this evening. idled and watched temp climb then drop (t-stat opened), then climbed again and settled about an 1/8th of inch to the left of 175 (see attachment). So, took it off the trailer and went and ran it hard for about a 1/2 mile. Needle climbed to between 1 and 7 in 175 then dropped a little. Stopped and idled out of gear for a bit. Normally, it would start to climb and die out once it went right of the 175 mark. this time, needle settled just to the left of 175 and stayed. Ran it hard again for 1/2 mile then went to launch and trailered. While on the trailer (in the water of course), let it idle for a while. again, prior runs it would pass 175 and shutdown. But like on the water, it settled to the left of 175 and did a little 1/16" deflection as stated above. I swear the temps were lower prior to t-stat change, but i think it was a 130 t-stat (it was hard to make out the middle number). The new one is a 150 tstat.
I shot the temp readings of the risers and manifolds and they were in the 105 - 119 range, and i was able to comfortably rest hands on top of risers (before they would start out fine then be scalding hot when engine shutdown). Never saw t-stat housing go over 155.
But...and there's a always a but right? I did notice some other issues.
- noticed a few drops of water between riser and manifold on oil filter side (probably gasket). There is no noticeable prior leaking at that point so i'm wondering if i was having RWP issues last year but didn't become major until i threw a new impeller into a bad RWP.
- noticed a backfire sound when throttle moved quickly to accelerate. Was completely random and wasn't out long enough to see if i could find a pattern to reproduce. doesn't do it at idle or medium throttle. Noticed same when old fuel cell was failing, and the last couple of times i've been out the past 3 weeks or so for trials (with new fuel cell installed) it didn't make this sound.
Sooo....yea, i think the overheat issue is resolved but any additional thoughts welcomed.
I knew i was going to have to some work on this when i bought it last year but am completely amazed the previous owner didn't do jack as evidenced by the gimbal bearing replacement last year the condition of the RWP discovered last week.
So my next plan of action is to address the riser to manifold leak. I dread pulling the risers off. Since i'm a noob, I'll be back to get opinions, in a new thread of course (i know i should probably replace, but funds are really tight due to Covid this past year and underwater strike last fall) so if they are fairly clean i hope i can limp by this year.
I also plan on changing the plugs. I was slated to do them last week but got wrapped up with the overheat issue.
Two other things i know i need / want to do, but will try to hold off till later in the year if at all possible is the circ pump (two sets of gaskets ordered but they keep coming back as wrong ones. they look like smaller versions of the t-stat housing gasket instead of actualy pics when seen online. Marine shop has now ordered VP gaskets instead of Sierra). The other thing i want to do is pull the lower unit and take a look at the water pickup tube. I've read some said theirs is brass while other's have stainless. Due to year, mine is probably brass. ANd i see the new ones are all stainless now.
So sorry for the length of this. I seriously appreciate everyone on this thread (and others i've asked for help on) for taking time to provide info, insights, and help....especially to this I/O VP noob! A ton of info provided in this forum has really helped, at least helped me, to understand and work on this thing as well as provide helpful keywords to crawl the web for additional info.
Thanks!
www.volvopentastore.com
