1997 johnson 35 hp 2 stroke power issues

[rammbo]

Hi guys ive purchesed a 1997 zodiac futura johnson 35 endevour i hav good compression,starts first pull,nice and quite,but find it hard to get up on plane and get any speed seems to lack power a 35 should hav ,is this moter big enough to get me going more than 15knots and tow a kneeboarder .im very dissapointed with the performance and any suggestions would b greaty appreciated.

[rammbo]

Originally Posted by rammbo

Hi guys ive purchesed a 1997 zodiac futura johnson 35 endevour i hav good compression,starts first pull,nice and quite,but find it hard to get up on plane and get any speed seems to lack power a 35 should hav ,is this moter big enough to get me going more than 15knots and tow a kneeboarder .im very dissapointed with the performance and any suggestions would b greaty appreciated.

also the motor sits on a 20mm block tilled on th 2nd hole in from the transom is this about right.

[Nos4r2]

It should do. Something is wrong with either the motor or the height it's mounted at.

What shaft length is the motor?

[rammbo]

Originally Posted by Nos4r2

It should do. Something is wrong with either the motor or the height it's mounted at.

What shaft length is the motor?

i think it is a longshaft what do i measure,the fin above prop is about level with bottom of transom and hav just noticed bottom of transum hangs down about 40 mm i think it should be level with the keel and this may b causeing some of my problems with drag but still think the motor is underpowered for some reason i thought a 35 on this boat wood pop it up on the plane easily.model no of motor is bj35aredg .

[9D280]

What prop you got on there?

Also if a SIB are the floor chamber(s) pumped to the correct pressure?

[rammbo]

Originally Posted by 9D280

What prop you got on there?

Also if a SIB are the floor chamber(s) pumped to the correct pressure?

10x15 prop what pressure for the keel do you suggest this may b problem too if its underinflated the boat did feel alittle bendy and wanted too bog down at the front.

[9D280]

No idea! Any Futura Owners reading this? (might be worth a parallel post in the "SIBs" section?)

Low keel pressure as you say will make it bend, so the prop won't be pusing you forward it will try to pull the transom under the hull, hence huge drag & no forward motion.

Does the transom "wiggle" relative to the toobs if you push & pull the engine case?

[rammbo]

The transum is solid, i believe im havn a number of issues at once compounding the poor performance underinflated keel and poor trimming ,and when throttle is at max i still get about 4 mm more movement on the carby inline linkages SHOULD THEIR B ANY MORE MOVEMENT THERE? im thinking its not flat out .also found a spilt in a sparkplug lead which prob not helping.

[9D280]

Ah, that won't help!

For what it;s worth, I have a 3 cyl whioch ran like a do until I changed the HT leads.... The following story is spread around the anals of the engines section, but suffice to say getting a decent spark showed up all the "adjustments" made by the previous owner and a trotal rebuild ensued....

Anyhow, back to yours I;d replace both leads - if one has gone there;s a high chance the other wil lbe not too far behind it. If it's a separate coil & lead, your local Auto factors are likely to stock what you need for sub £20 or equivalent Auzzie Dollars.

As for the throttle linkage, that might have an effect - you'll need to take the cover(s) off the air box & look into the carbs. Check the plate goes fully 90 degrees. Most engines of the vintage I think yours is will advance the spark as the first thing the throttle cable does -opening the throttle in the carb follows on, with either a damped lever or a cam follower on a shaped plate of some description so the slack may be there for a reason.

If you have a broken HT lead then I'd change them both first before fiddling. Probably worth a new set of plugs as well while you are there.

Nobody got a keel pressure yet?