Well, we did check the compression on cold engine and all was good, also no major visible burns, however it was always flooded when heads came off...
I will let you know, if I am that happy in September :)
It was checked as well - and was OK. Consensus here seems to be linked to dead valve springs - during 3000 rpm excaust valve stayed mostly open and overheated that one spot, when cooling down with sea water, it made it crack
All manifolds were faulty in the same spot.
I do hope that it will...
So! 3 trips made and it seems to be fine now.
What was done and what fixed it - I have no F***ing clue:)
New valve springs, heads done, all new gaskets, left and right side heads were swapped, new manifold. Engine is running better and not so big difference between port and stb engine anymore on...
Sorry to disappoint you - Searay Sundancer has a muffler in the middle so there can not be hydrolock from water getting in from exhaust. Exhaust pipes are on the side of the boat hence sudden stop will not get the water in. I am not sure how other boats are done, but this IS NOT the issue here...
Went to the boat today and made a short clip of the heads, here you go:
https://www.dropbox.com/scl/fi/18ofm7g8en376nqgy5t6s/2025-03-24-14.32.05.mp4?rlkey=0s45svoylnnjqhn6mm3nuwwxq&st=ng9jmgmx&dl=0
Should not be the issue that they are so bad. Will replace the springs. And all the contact...
Heads are good and tested - will try to make better pictures with proper light. Those were done in the dark below the boat. Water part was pressure tested and each valve separately tested for leaks. IRL they are good and nice. On Friday will try to go to the boat and unwrap them and make better...
After not finding anything else, one (last) idea came: valve springs :) Will swap those for new ones.
Doctor AI gave this out:
Reduced Power & Overworking the Engine – If the engine struggles to produce power due to valve issues, you might push it harder to maintain performance, leading to...
I do have 2 (two) engines and during my time all 4 of the manifolds are changed - all of them are from RecMar and are working fine (minus the always broking one). Whole last summer I had issues with one side of the one engine, did swap the manufacturers, but I did not put the used working one to...
Yes, always the same side
Yes - this was straight, we will check once more as it is easy to do now
That we have not done, but all bolts go tightly and they feel like they are fine, but worth to check, as I do not have any other ideas...
thank you!
Märt
Like you mentioned earlier, 8 pages and hard to read and understand:) However - previous post stated that different brands are used, means one was done by Recmar and another one was done by Sierra. Both different castings forms.
I have two engines with 4 manifolds - only one of them is cracking. Last one did two trips and is broken again. Two different manufactures.
We used the thermal gun to measure temps on the run and on idle, no major differences between manifolds or engines. Also added see thru pipes to see if the...
Three point connector with ball was replaced to brand new one, no difference :( Ball is working nicely, you can close it by blowing inside.
We will go thru the pipes just to avoid that there is part of impeller or anything funny blocking the water on higher flow.
out of ideas. I did order brand...
