'83 Hunter 34 engine vibration and overheating

[Win]

I've had a bad engine vibration for the past 2 years. I changed the engine mounts, and cutlass this year hoping to fix the problem. The vibration only happens in forward gear after the engine has been running for awhile, and only from a dead stop(<1 knot). If the boat is moving forwards about 2 knots it never vibrates. If the engine is cold, it never vibrates! Once it stops vibrating it doesn't re-occur until I stop the boat. Pulling away from fuel docks in the wind has been tough!One day I was running at about 2800 and the engine overheated. Dropped back to 2400 and continued on.Next day I flushed the coolant with radiator flush, and fluched it about three more times till the coolant came out clean. It has stopped over heating the vibration problem has gone away. The only thing I can figure is that the motor mounts soften when it gets too hot.About five years ago I had a similiar problem with the overheating. I didn't know what the problem was and went thought the usual hoops. Check the sea water intake line/strainer flow, replaced the impellor(sp?) on the sea water pump, and even replaced the thermostat. The overheating problem didn't go away. I then tore the heat exchanger apart! The heat exchanger core was clean on the sea water side. However the cooling tubes on the fresh water side were coated with a layer of scum. With very little access to the assembly I could only hose out a little bit. After I put the unit back together I used a radiator flush and flushed it several times. The overheating went away!I guess I just want to share my experience with the others that have been having overheating/vibration problems.

 

[Joe M]

Me too

I just bought my 83 H34 in June. My engine rattles when I put it into foward gear until I get it up to about 2000 rpm's. Then it settles down. At that point I can lower the rpm's with no problems. It just occurs when I increase from 800 - 2000.Another problem I have is that the rpm lever on the binicle only stays in position up to 2000 rpm's. After that I need to hold it in place if I want to increase go over the 2000 mark. Any idea's on how to fix the lever? Thanks.

 

[Steve Dion]

Joe M, you have a case of throttle creep.

Joe:Take a look in the photo forum. There is a Morse part number for the 'J Clamp' that will help you with throttle creep. You can either search on my name 'Dion' or 'Throttle' and you should find the article.

 

[Scott]

Joe - Instead of a clamp use a tennis ball

The clamp could cause wear on the cable. Knife a a hole in either side of an old tennis ball and slip it over the throttle lever. Not an fancy solution, but a cheap one!Scott83-H34-188 Island Hops

 

[Steve Dion]

Scott

Scott:The 'J-clamp' is actually a Morse part, made for their cables and recommended by the Yanmar service people. We have been using one for several years without any problems. The cable is just another maintenance item. Every so often you need to replace them. I doubt that the clamp is going make ANY difference in the life of the cable. They usually corrode and break first anyway. To each his own ideas, but for $20 you end up with a nice clean solution that works.

 

[Joe O]

Throttle Cable tension

Another solution if you have the Merriman pedistal is to remove the compass off the pedistal. This exposes the throttle lever linkage. You will notice that there is a cap screw above the shaft which is connected to the throttle lever. Tightening this capscrew will add friction to your throttle lever shaft and thus counteract the force of the throttle spring. I also have the J-clamp, but I have disconnected it when I discovered this capscrew. The system works fine now! Goodluck!JoeO