1989 Johnson 70hp compression Boat Inspection

[Vickypoint]

I am looking at a buying a boat fitted with a 1989 70hp Johnson motor. It has been compression tested and has a reading of 110psi on all cyclinders. Can anyone tell me if these figures are OK.

The boat has been used a lot but looks very well kept. No running hours are known.

Can anyone recommend a good boat inspection service. The boat is near Redcliffe.

;D
Vickypoint

[Noelm]

as long as all cylinders are the same (or close) it will be fine, pretty simple Motor, make sure of rust and corrosion around all the bolts and things, they tended to rust up a bit. I am sure someone will jump in that can either help you inspect it, or let you know someone who can.

[FNQCairns]

If say 125 is fairly typical of a low-medium hour engine then 110 will denote how much work the engine has done (quite a bit) and more importantly how much service life it may have left, I forget what is appropriate for these engines but if it where me I would be nailing what full compression is on them first.

Also if this is the original engine and all are even at 110 (lovely and even but pretty tired??) this will also perk my interest, it does happen and there are only 3 cylinders not 6 but still.....worth investigating because the engine if by unlucky chance you only get 4 months (or less) out of it??........it does happen.

cheers fnq

[pursuit001]

hi mate ive been in the marine game alongtime and know quiet a bit those readings are ok as long as there all even and arent within 10 or 15psi within each other needless to say it would be nice to see them up around the 120 125 mark perform a warm compression test on it and see how you go whos to say the engine could last 4 more years sand possibly only go for another 12 months

[CRAFTY24]

Hi,

I recently sold a boat in the Redcliffe area that had the same motor on it (it's not a 15 ft cruisecraft by any chance?) I had a compression test done before I sold it and it had 130,127,127. I would think that 110 it might be a bit on the tired side. I am not a mechanic but I will probably be giving it a miss. How much does he want for it? If he is only asking a low price then you need to way up is it worth it.

As I live in Redcliffe I can very much recommend Wade Wiemers. He is in the Clontarf industrial area and his mobile number is 0437 733 056. I have used him a couple of times as recommended by others on this forum. He will look after you and won't charge you a fortune.

Let us know how you go.

Dave