yamaha 3.0 l4 blew head gasket help!

Ive got a 1993 Harris Flotebote with this engine sterndrive combo and i have redone most of the boat with new, floors,carpet,seats etc so i don't want to dump it or trash it . i have had the lower unit rebuilt and has new bellows also. pulling a tube with grandkids must have been too much for my old girl and it started ticking and missing and smoking . i pulled the valve cover and i have water in the oil up top . The dip stick oil wasn't milky or even thin so i think i blew head gasket . i cant find new parts or many used parts but would like to know if i can use a automotive engine cyl head from a gm 181 ci 4 cyl chevy and also if i can can i put a mercruiser exhaust manifold on it . i had a leak on the manifold before and we bought a mercruiser one that would bolt up but the exhaust ports were not the same . if i replace head with one that matches the mercruiser ports is this possible or can someone tell me what my options are because i want to fix the engine for sure thanks and sorry for the book . thanks Tom

if i can use a automotive engine cyl head from a gm 181 ci 4 cyl chevy and also if i can can i put a mercruiser exhaust manifold on it . i had a leak on the manifold before and we bought a mercruiser one that would bolt up but the exhaust ports were not the same . if i replace head with one that matches the mercruiser ports is this possible

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Ayuh,..... Welcome Aboard,...... Chevy has never used that motor in a car, nor a truck,.....
You can use Mercuuiser parts for yer motor though,....
It don't matter if the exhaust ports are the big ones or the little ones, the manifold will still work,....
Marrying it to yer Yamaha outdrive exhaust port is what's necessary,....
As for gaskets, 'n internal motor parts, Merc or Volvo pars will work,....

thanks for reply the ports on the head that mercruiser offers reman heads there are 8 ports and on my yam there are only 6 . i remember the manifold we bought 1/2 of the port would have been blocked if we bolted it to the head .wouldnt that cause flow issues , loss of power or cooling something like that. im just trying to figure out what i can do to get the motor back running before next season without spending a fortune . i tried to attatch a picture of the diagram fromcrowley marine but it wouldnt let me

Bondo sorry to go on lol but there is a local boat guy I've known for 40 years that has a few 3.0 inline 4 cyl motors i think 1 is a Volvo and one is a mercruiser , he has 5 or 6 manifolds but the ports are different than my head . your saying that doesn't matter so could i bolt one of the heads from his motors to my block and use either a mercruisr manifold or even try to resurface my manifold and use that to keep from having the elbow assembly issues . if not willl one of those manifolds have a elbow assembly i can use my rubber boots and clamps etc with and do you know where i can source the new gaskets for the yam if i reuse it

now im really confused because another post where a guy wanted to swap yam parts for mercruiser they said he needed to swap all the wiring ,lower unit ,and much more . im just wanting to basically do a head gasket job or head swap to get my boat running again . i want to use my block and all my exhaust parts im ok with swapping head and manifold to mercruiser if it will work but you said marrying the mercruiser manifold to my yam exhaust might be big issue

Why not get the head resurfaced ? A few years back my 3.0 Merc had a head gasket go bad. Mechanic told me that was common if the engine ever overheated. Pulled the head, took it to local engine shop, they resurfaced the head, reground all the valves and reseated them, along with new valve springs. A little over 300 bucks total for the shop. Block deck was flat and no scores in the cylinders. Put everything back together in an afternoon and ended up with compression 147-150 across all four cylinders and she ran like new ! Pull it apart and see what you really need, if cylinders are good, you might just need the head reworked, far better to rework than gamble on a used one !!

Get a complete Volvo or Mercruiser 3.0 long tail and swap out to replace all the Yamaha stuff that is no longer supported

Be sure to seal the head bolt threads with #2 Permatex or similar compound. Torque the bolts to 100.

kenny nunez said:

Be sure to seal the head bolt threads with #2 Permatex or similar compound. Torque the bolts to 100.

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AND....be sure to run a tap into those holes to clean the threads or you could get a false torque reading.