Selva Overrevving

[Phil Robinson]

Pete,
Thanks for the advice again. I'm trying to avoid lifting the engine, not because it's difficult (I have access to full workshop facilities including a crane), but for 2 other reasons. Firstly, it's had more than it's fair share of bolt holes drilled over the past 17 years for different engines. I reackon it's on at least it's 4th or 5th engine so far. As you know, each repair weakens the transom. Also, if you look at the pics, you'll see that there is very little room left for upward movement at the top of the transom (in relation to the upper retaining bolts).

The prop probably isn't giving me as much as I should get. I don't have a rev counter (no room) but my GPS told me this week end that I got 28.5 knots at full belt. I guess that's slow?

With regard to the fuel, it's 4 weeks old. I try to use it within 6 weeks of purchase. Am I wrong with this? I'll give the carb cleaner a go. Just squirt straight into each carb, one at a time, whilst running, is that right?

Ic0021,
Thanks for the reply. This had an Evinrude 65 on it when I 1st got it. It pulled badly once I had a full quota of divers & gear on board & eventually just gave up. I went up to a Merc 80 but that was the biggest pile of trash ever. Not there's anything wrong with Mercs, I just couldn't see myself being ripped off. It was a 1969 "recon" that had just had a bit of a paint & clean up job. Bye bye pistons rings, crank, rods, the lot. The Selva 100 came a good price & fitted well. So I thought 4 divers, silly amounts of kit & a pretty strong boat can handle it. Or am I barking up the wrong tree again.

Thanks to all for the feedback - it really helps me get to grips with the subject.

[Pete7]

Phil, leave the bolts were they are, just use a different set of holes in the engine saddle (frame bit that touches the transom). there are normally 5 or 6 bolt hole options. Your bottom bolts just live in slots.

The prop probably isn't giving me as much as I should get. I don't have a rev counter (no room) but my GPS told me this week end that I got 28.5 knots at full belt. I guess that's slow?

not with the small 15" prop however you could easily exceed the max revs lightly loaded. Trip to Bill highman for a second hand rev counter would be a excellent idea to get the prop size and revs right.

With regard to the fuel, it's 4 weeks old. I try to use it within 6 weeks of purchase. Am I wrong with this? I'll give the carb cleaner a go. Just squirt straight into each carb, one at a time, whilst running, is that right?

spot on

So I thought 4 divers, silly amounts of kit & a pretty strong boat can handle it. Or am I barking up the wrong tree again.

Nope good choice for 4 divers and 28 knots will be fast enough for a dive boat less the kit gets dmaged, a 15" prop might be the ideal size afterall with all that weight, because divers in this country are not going to be svelte are they

[Mike G.]

Motor should be mounted so that the anti-cavitation plate is no more that 2 cm below bottom of hull. Assume you have a pre-mix version i.e. you are mixing the oil with the fuel in the tank - should be a 50:1 ratio using only an Outboard Two-stroke oil. The standard propeller for this model was 13" dia x 16" pitch - max RPM at full throttle should be between 5000 to 5500 RPM. Suggest fitting new spark plugs use NGK B8HS gap at 0.6mm. Carb. air screw should be set at 1 to 1.5 turns out from lightly closed position - in neutral gear the engine should tick over at approx 1200 RPM - 800 RPM in gear .... if you send me a private email with your postal address will send you a drawing of carb. and settings.

[Phil Robinson]

Pete,
Divers like food n drink too much. I'm not so small myself! Problem is, we break boats quicker than we can repair them. You guys should have seen the sea state at the Farnes (NE England) towards the end of Sunday. Her ladyships nose is flat so, over the 1st wave & straight through the next and again & again.
Great fun though!
Cheers to all, will keep fiddling & will let you all know if I can squeeze a little more out of her.