Mariner 9 HP compression issues

[inlandlake]

I have had this small outboard 2 stroke motor ( on a 12 ft aluminum boat) for two years after buy from a friend at church that bought it new in 1992. He used it earlier on but not much before he sold it to me . After I bought it two years ago it started very easily and continues to start very easily. However last year it would run for about 30-45 seconds and bog down and it would easily start up again but then do the same thing 30 seconds later . I brought it in and they cleaned the carbs and at the end of the season I took it back out and the same thing happened so I put it away for the season. This year I changed the gas , plugs, ignition coils. The same thing happens bogs down easily but starts up easily and when running runs fine for about 30-45 seconds and gets the boat moving very well and up to speed. I took the motor in this week and they said it was probably the fuel pump and maybe the bulb and tube had debris ( very old tube) and was feeding fragments into the gas causing a supply issue. They called yesterday and stated the compression was 45 in both cylinders. I found this odd because it runs so well for 45 seconds. Thoughts? I didn't think a motor would run well with compression as low as 45. is the compression check they are doing reliable? The mechanic said I he would try to rebuild the fuel pump and clean the carb but didn't guarantee anything. Thanks for your thoughts about the compression.
Austin

 

[racerone]

Are you mixing gas and oil at 50:1 in the tank ?----Did you install a new water pump impeller ?---A 9.9 HP ??-----Serial number?

 

[inlandlake]

yes 50:1 in the tank then well mixed, 9.9 hp serial number OC268922. I did not install a new water pump impeller but there is a steady get of water flowing out which if figured indicated the cooling system was intact.

 

[QBhoy]

Floats sticking. Clean the carbs well. She’ll be fine. It will be a 9.9hp you have. Made by merc. Can also be converted to 15hp fairly easily. Great engines. Check the fuel primer operation she has. Not technically a choke, rather a prime system they have. Make sure it’s not sticking and working properly.

 

[racerone]

Bring it home and do the compression test yourself.-----If it is indeed 45 PSI it will need some serious work.----I believe you can remove bypass covers to look at pistons and rings.

 

[QBhoy]

Bring it home and do the compression test yourself.-----If it is indeed 45 PSI it will need some serious work.----I believe you can remove bypass covers to look at pistons and rings.

I think if it actually was that low…a quick look down the plug holes with a torch would tell a story of things. Really doubt it actually is though.

 

[racerone]

We can not see / touch these motors.----Posters need to do the inspection and report what they find.----There is no magic to this.