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Probably not the correct forum but ...... Cavatation????

B

bmdakk

Member
Ok I have a 1986 crest 25 foot pontoon, New to me. 50 HP evinrude ( 86 also) (e50belcde) Got the motor running great and it pushes the boat along at a pretty good clip, However, I noticed that the motor doesnt set down on the transom all the way. it is bolted to it but the lip that would rest on the top of the transom is off about 2 inches. I can see where someone who had it before me had drilled new holes to put the motor in the current position.. My problem I noticed today when I took it out is that it has real bad cavatation at WOT going straight. I figure it is where the motor is raised, but upon further inspection I can see that the motor skeg would be touching the ground if I lowered the transom plate. I am gonna replace the transom anyway as it appears to be starting to rot. Do you think by lowering the plate back down will fix the cavitation? would a hydro fin help any. Im just not sure what to do about this.. While just sitting in the water the cavatation plate is about 4-5 inches under the water level but at WOT I can see the cav. Plate. Thanks.
 
Pontoon boats are not my cup of tea.... however fi the engine is actually cavitating (prop drawing air), then the prop is too close to the surface of the water.

The problem exists that should you lower the engine; will it be too low and encounter a "drag" problem?
 
can the motor be tilted for trailering?a lot of boats have to be tilted as the skeg is too close to the ground while on the trailer...
 
Yes the motor can be tilted and Locked in the up position, However the skeg would drag when I lower it to back it down the ramp. Here are some pics... and Yes the transom is getting replaced this weekend.












The last one shows the waterline at Idle. When underway the level sets right at the Cav plate and I can see the top.
 
dont you have a release on that motor where you can launch and then release the motor to come down to operating position?and tilt it once you are on the trailer and start to pull boat out?...there are a lot of launches and boats where you have to do that anyway...i use power trim now to trim up on launching just as a precaution...i ran 50.s for years where i had to latch up and release once i got into the water..
it looks like from your pictures that the motor was bolted through the top hole at some point which would help your performing problem......
 
yes it does have a lever I can flip to let the motor down, forgot about that. My luck though is I would forget about raising it when pulling it out of the water. Im kinda new at the boat thing, dont know the tech terms. would lowering it to the top hole cause drag?
 
Sounds like you need to lower the motor one hole at a time to get the best performance then raise the trailer bunks so you don't drag the skeg.
 
agree on trailer adjustment...thought about that and didnt enter it...you say you are new to boating...i think we all have a mental checklist we develop before launching and before loading on trailer...also before hitting the highway...its just part of boating...i would venture to say that the majority of us have launched a boat without the plug in at least once...good luck and enjoy your rig...
 
Dont Have a Bunk Trailer Have an old 1984 Scissor Trailer. and its cranked up all the way.




Yes , when growing up My parents have launched numerous times without a plug. Ive been around boats when I was younger (43 Now) My parents have had everything from a tracker 17 bass boat, galaxy ski boat and 24, and 20 foot Pontoons. I am familiar with how to run and operate a boat safely, Just new to ownership and the Maintanence., Oh and I hate the trailer and am looking for a Bunk style. Loading on this trailer is totally different challenge from what I am used to.
 
''Loading on this trailer is totally different challenge from what I am used to.''.....lol..i would love to see a video of you loading it on that trailer....also the look on a state troopers face when he see's it on the hwy...
 
Its really not that bad . I just have to get in the water and float it to center then winch it up as far as it goes. The transom is Out and the New one is drying( resin) as we speak It will go on tomorrow. I do have a Motor toter When I trailer the boat so it doesnt bounce and is in The UP position. I will find me a Bunk trailer one of these days.
 
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