Background info - 23hp home built SD w/o clutch on a 1648. It still has the stock carb!! I set the idle high (out of the water), so when I lowered the prop into the water, the boat would idle along w/o me having to give it any gas.

Problem - I have since added a clutch and I don't want to engine idling at 2000 rpm's. I took the boat out yesterday and lowered the idle to around 1200 rpm's but when I engage the clutch, the engine boggs so bad it dies. This was tested in deep water w/ the prop set at the correct height.

Motor has a cam installed and I have a 34mm mikuni on the shelf in my shop. Would the mikuni help this problem and if not what will. Buying a new motor isn't an option. I have been building this one for almost a year and I feel like I'm married to it.

So no one has every experienced this before??

What kind of prop you have on there? May have too much cup for your motor if its idleing at 1200rpms and then dies when you engage, have you gotten it up to speed if so what RPMS are you running at full throttle?

Do you have after market exhaust? What cam is it? There could be numerous contributing factors, give me some more specs on what done to the motor

The prop is 11x10 and it's turning about 3700 rpm's wot.

Cam came from performance v-twins....he said it was about a 280 grind. I have a 10 deg advance timing key but havent put it in yet. Stock exhaust but looking to get aftermarket soon.

Also forgot to mention, my pulley ratio is 1:1.2. 40 top and 48 bottom pulley