Sealine 328 wont get up on the plane

Claytos

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Hello,

I have a Sealine 328 with the twin petrol engines. They both rev freely when not engaged up to 5000rpm. However, once underway, they will only go up to about 2500 and I cant get her up on the plane. She's only achieving about 13knots flat out. The underside and props are clean and she's only just started doing this - any ideas ?
cheers

/forums/images/graemlins/confused.gif
 
Ah Rococco nearly bought her about 6 years ago before we found our 328. Beautifull condition or she was then /forums/images/graemlins/grin.gif. What are the leg trims and tabs doing?
 
Legs and tabs are all down and clean so shouldnt stop her getting up - and she's still in beautiful condition, especially with the new covers on /forums/images/graemlins/ooo.gif
 
Are you sure the underside is clean - I had the same problem on my boat - nothing really visible down the sides - but had her hauled out and cleaned off and suddenly behold - 25 knots again.

Yesterday I noticed that slime had started to build up again after only a week. Agood blast in the Solent soon got rid of it though
 
I did post with the same prob last season - and that was slime and zebra mussels. She's very clean now though but showing a very similar problem.
 
Dont know what to suggest then sorry, but does sound like shes down on power there are all sorts of things it could be with diesel but dont know with petrol. Are you looking after the engines yourself?
 
If it's not prop or hull fouling then a bit of logical problem solving is next.
Next time you're out run it flat out with just one engine and note speed and RPM then the same for the other. If the results are the same then it's something both engines share in common, like the hull for example. Have a brainstorm on what other common items are shared by both engines....there are not many!
If the results are different then get back on the forum
 
The chances of both engines having the same mechanical or ignition problem at the same time is tiny unless the problem manifested itself straight after a service action.

Fuel starvation on a petrol normally presents other symptoms (running hot, misfire) which should be clear. Given that each engine will have its own pumps and carb/Fi system even the chance of fuel starvation affecting both engines to precisely the same degree should be slight (apart from total loss of fuel of course).

That still leaves the condition of the bottom, prop efficiency and weight as prime candidates. Carry out the single-engine test as above, any problems with one of the props should show up there (although a bushed prop should allow the revs on that engine to increase anyway) and you can investigate as appropriate. Assuming you haven't suddenly loaded her up with lots of weight then it comes back to really how clean is her bottom - right underneath???
 
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