86-87 Mariner 150 questions

[Mspencer1776]

I bought a 87’ stratos 179v with a mariner magnum 2.0l 150 on it. I had a 4 blade 22p prop on it and hit a rock at idle with it. Replaced it with a tempest plus 24p. I was running into heat issues at WOT before the prop change so I also changed out water pump and thermostats. Got it out today and it seemed to be peeing better but started to overheat after my initial run across the lake. Could it be overheating from a bad poppet or possibly the motor sitting too high? It has the cavitation plate about 1.5” above the bottom of the boat. I’m also only hitting 5000rpm and 45.4mph at WOT. Prop pitch and motor location were recommended but a stratos owners group I belong to.

 

[jimmbo]

Time for a Compression Test, and Spark Test(jump a 3/8" gap)

I suspect there is a bit more to this Story....

 

[Dukedog]

thats a lotta prop for a little 2 liter!!!.. what 4 blade was it?.. do you have a water pressure gauge?

 

[Chris1956]

That is a lot of pitch for that boat/motor combo. A 21"P prop would probably be max.

The poppit controls cooling at high speed. If that is where she is overheating, it is a possible candidate. Make sure you get the exact poppit kit for your year and model motor, as they changed over the years.

 

[Mspencer1776]

thats a lotta prop for a little 2 liter!!!.. what 4 blade was it?.. do you have a water pressure gauge?

It was a turbo prop, and water pressure was up to almost 15 at WOT

 

[Mspencer1776]

Time for a Compression Test, and Spark Test(jump a 3/8" gap)

I suspect there is a bit more to this Story....

Compression in 118-120 on 5 cylinders and 112-113 on the sixth and spark is good.

 

[Mspencer1776]

That is a lot of pitch for that boat/motor combo. A 21"P prop would probably be max.

The poppit controls cooling at high speed. If that is where she is overheating, it is a possible candidate. Make sure you get the exact poppit kit for your year and model motor, as they changed over the years.

That’s what I thought about the pitch as well but I had multiple people telling me they run 25p with that set up.

Looks like there are two styles of poppet for my model. Guess I’m going to need to see which I have. I’m guessing I should change everything behind the cover?

 

[Chris1956]

Change as many parts as you can. I think the carrier was to hard to get out, and didn't look worn, so I left it original.

I run a 16 foot (about 1000# with motor and gas) speedboat with that motor. She will swing a 23P prop, but the hole shot is a bit sluggish. She would probably swing a 24-25P prop, with a decrease in max RPM and acceleration. I usually run a 21P prop as I get top acceleration and max RPM. I might be able to get more speed (65+MPH) with a 23P prop.

 

[Dukedog]

if you poppet has a two bolt cover tha its gonna be part #65663A2
if it has a four bolt cover its ganna be part #14462

It was a turbo prop, and water pressure was up to almost 15 at WOT

turbo explains alot!.. not one of tha favorites.. pressure should be 3 ta 7 at idle and 12 ta 18 at wfo..... when ya changed tha pump did you replace it all or jus tha impeller?

would like ta see tha 2.0 tha turns a 25 tempest that high... jus remember bass boat guys are STILL FISHIN" GUYS!......... even tha stratus guys.....